Remove unnecessary array filter

Remove a filter callback which always returned true. The first `!ann.id`
condition is already part of the `store.unsavedAnnotations` logic. The
second `isHighlight(...)` check did not work properly because the input
was an annotation stub object with only `id` and `$tag` fields instead
of the `Annotation` that `isHighlight` expects. For annotation stubs
with no id, it always returned false.

From a functional perspective the `isHighlight` check was also
unnecessary. `store.unsavedAnnotations()` only returns IDs of
annotations which have active drafts, but for highlights no draft is
created.

src/sidebar/components/ThreadList.js

@@ -2,7 +2,6 @@ import { useEffect, useLayoutEffect, useMemo, useState } from 'preact/hooks';
 import debounce from 'lodash.debounce';
 
 import { ListenerCollection } from '../../shared/listener-collection';
-import { isHighlight } from '../helpers/annotation-metadata';
 import {
   calculateVisibleThreads,
   THREAD_DIMENSION_DEFAULTS,
@@ -94,11 +93,7 @@ function ThreadList({ threads }) {
   const newAnnotationTag = (() => {
     // If multiple unsaved annotations exist, assume that the last one in the
     // list is the most recently created one.
-    const newAnnotations = store
-      .unsavedAnnotations()
-      // @ts-expect-error - FIXME: The `isHighlight` check here will always fail
-      // because `unsavedAnnotations` returns objects that do not have a `$highlight` property.
-      .filter(ann => !ann.id && !isHighlight(ann));
+    const newAnnotations = store.unsavedAnnotations();
     if (!newAnnotations.length) {
       return null;
     }

src/sidebar/components/test/ThreadList-test.js

@@ -9,7 +9,6 @@ import mockImportedComponents from '../../../test-util/mock-imported-components'
 
 describe('ThreadList', () => {
   let fakeDomUtil;
-  let fakeMetadata;
   let fakeTopThread;
   let fakeScrollContainer;
   let fakeStore;
@@ -32,9 +31,6 @@ describe('ThreadList', () => {
     fakeDomUtil = {
       getElementHeightWithMargins: sinon.stub().returns(0),
     };
-    fakeMetadata = {
-      isHighlight: sinon.stub().returns(false),
-    };
 
     fakeScrollContainer = document.createElement('div');
     fakeScrollContainer.className = 'js-thread-list-scroll-root';
@@ -71,7 +67,6 @@ describe('ThreadList', () => {
     $imports.$mock(mockImportedComponents());
     $imports.$mock({
       '../store/use-store': { useStoreProxy: () => fakeStore },
-      '../helpers/annotation-metadata': fakeMetadata,
       '../util/dom': fakeDomUtil,
       '../helpers/visible-threads': fakeVisibleThreadsUtil,
     });