Fix flakey ProfileModal tests

The ProfileModal tests would sometimes fail with this error:

```
FAILED TESTS:
  ✖ "after each" hook for "shows modal on "openProfile" event"
    Chrome Headless 129.0.0.0 (Linux x86_64)
  Error: Failed to execute 'showModal' on 'HTMLDialogElement': The element is not in a Document.
```

The `HTMLDialogElement.showModal` call happens in an effect when the
`ModalDialog` component is rendered with the `isClosed` prop set to false. In
the ProfileModal tests, the component was rendered in a disconnected DOM node,
so this error should have happened on every run. However the
`emitter.publish("openProfile")` call which triggered this render was not
wrapped in `act` and so the effect which calls `showModal` was scheduled, but
often did not actually run before the component was unmounted in the `afterEach`
hook.

Fix the issue by:

 - Wrapping all `emitter.publish("openProfile")` calls in `act`, so they
   synchronously execute the effect.
 - Rendering the `ProfileModal` component in a connected DOM container
   which is removed after the test runs
 - For consistency, update the `NotebookModal` tests to work in the same
   way as the ProfileModal tests, with a single container element which
   is removed at the end of the test

src/annotator/components/test/NotebookModal-test.js

@@ -8,6 +8,7 @@ import NotebookModal, { $imports } from '../NotebookModal';
 describe('NotebookModal', () => {
   const notebookURL = 'https://test.hypothes.is/notebook';
 
+  let container;
   let components;
   let eventBus;
   let emitter;
@@ -15,21 +16,20 @@ describe('NotebookModal', () => {
   const outerSelector = 'dialog[data-testid="notebook-outer"]';
 
   const createComponent = config => {
-    const attachTo = document.createElement('div');
-    document.body.appendChild(attachTo);
-
     const component = mount(
       <NotebookModal
         eventBus={eventBus}
         config={{ notebookAppUrl: notebookURL, ...config }}
       />,
-      { attachTo },
+      { attachTo: container },
     );
-    components.push([component, attachTo]);
+    components.push(component);
     return component;
   };
 
   beforeEach(() => {
+    container = document.createElement('div');
+    document.body.append(container);
     components = [];
     eventBus = new EventBus();
     emitter = eventBus.createEmitter();
@@ -46,10 +46,8 @@ describe('NotebookModal', () => {
   });
 
   afterEach(() => {
-    components.forEach(([component, container]) => {
-      component.unmount();
+    components.forEach(component => component.unmount());
     container.remove();
-    });
     $imports.$restore();
   });
 
@@ -70,7 +68,9 @@ describe('NotebookModal', () => {
     assert.isFalse(outer.exists());
     assert.isFalse(wrapper.find('iframe').exists());
 
+    act(() => {
       emitter.publish('openNotebook', 'myGroup');
+    });
     wrapper.update();
 
     outer = wrapper.find(outerSelector);
@@ -86,7 +86,9 @@ describe('NotebookModal', () => {
   it('creates a new iframe element on every "openNotebook" event', () => {
     const wrapper = createComponent();
 
+    act(() => {
       emitter.publish('openNotebook', '1');
+    });
     wrapper.update();
 
     const iframe1 = wrapper.find('iframe');
@@ -95,7 +97,9 @@ describe('NotebookModal', () => {
       addConfigFragment(notebookURL, { group: '1' }),
     );
 
+    act(() => {
       emitter.publish('openNotebook', '1');
+    });
     wrapper.update();
 
     const iframe2 = wrapper.find('iframe');
@@ -105,7 +109,9 @@ describe('NotebookModal', () => {
     );
     assert.notEqual(iframe1.getDOMNode(), iframe2.getDOMNode());
 
+    act(() => {
       emitter.publish('openNotebook', '2');
+    });
     wrapper.update();
 
     const iframe3 = wrapper.find('iframe');

src/annotator/components/test/ProfileModal-test.js

@@ -7,6 +7,7 @@ import ProfileModal from '../ProfileModal';
 describe('ProfileModal', () => {
   const profileURL = 'https://test.hypothes.is/user-profile';
 
+  let container;
   let components;
   let eventBus;
   let emitter;
@@ -19,12 +20,15 @@ describe('ProfileModal', () => {
         eventBus={eventBus}
         config={{ profileAppUrl: profileURL, ...config }}
       />,
+      { attachTo: container },
     );
     components.push(component);
     return component;
   };
 
   beforeEach(() => {
+    container = document.createElement('div');
+    document.body.append(container);
     components = [];
     eventBus = new EventBus();
     emitter = eventBus.createEmitter();
@@ -32,6 +36,7 @@ describe('ProfileModal', () => {
 
   afterEach(() => {
     components.forEach(component => component.unmount());
+    container.remove();
   });
 
   it('does not render anything while the modal is closed', () => {
@@ -42,7 +47,9 @@ describe('ProfileModal', () => {
   it('shows modal on "openProfile" event', () => {
     const wrapper = createComponent();
 
+    act(() => {
       emitter.publish('openProfile');
+    });
     wrapper.update();
 
     assert.isTrue(wrapper.find(outerSelector).exists());
@@ -54,7 +61,9 @@ describe('ProfileModal', () => {
   it("removes the modal's content on closing", () => {
     const wrapper = createComponent();
 
+    act(() => {
       emitter.publish('openProfile');
+    });
     wrapper.update();
 
     assert.isTrue(wrapper.find(outerSelector).exists());