Don't clear filters when clearing selection

When focus filters are in use (eg. user / page filters) it is annoying if
clicking a highlight in the document and then clearing the selection has the
effect of disabling the focus filters. Instead the plan is to have the selection
temporarily replace filters when active.

src/sidebar/store/modules/filters.ts

@@ -176,16 +176,6 @@ const reducers = {
       focusActive,
     };
   },
-
-  // Actions defined in other modules
-
-  CLEAR_SELECTION() {
-    return {
-      filters: {},
-      focusActive: new Set<FilterKey>(),
-      query: null,
-    };
-  },
 };
 
 // Action creators

src/sidebar/store/modules/test/filters-test.js

@@ -179,22 +179,6 @@ describe('sidebar/store/modules/filters', () => {
         assert.deepEqual(store.getFocusActive(), new Set(['user', 'page']));
       });
     });
-
-    describe('CLEAR_SELECTION', () => {
-      it('responds to CLEAR_SELECTION by clearing filters and focus', () => {
-        store.changeFocusModeUser({
-          username: 'testuser',
-          displayName: 'Test User',
-        });
-        store.toggleFocusMode({ active: true });
-
-        assert.deepEqual(store.getFocusActive(), new Set(['user']));
-
-        store.clearSelection();
-
-        assert.deepEqual(store.getFocusActive(), new Set());
-      });
-    });
   });
 
   describe('selectors', () => {