Revert Firefox composer delation hacks

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

src/components/views/rooms/BasicMessageComposer.tsx

@@ -499,9 +499,6 @@ export default class BasicMessageEditor extends React.Component<IProps, IState>
             handled = true;
         } else if (event.key === Key.BACKSPACE || event.key === Key.DELETE) {
             this.formatBarRef.current.hide();
-            if (!event.ctrlKey && !event.metaKey) {
-                handled = this.fakeDeletion(event.key === Key.BACKSPACE);
-            }
         }
 
         if (handled) {
@@ -567,29 +564,6 @@ export default class BasicMessageEditor extends React.Component<IProps, IState>
         }
     };
 
-    /**
-     * TODO: Remove when Debian moves to newer version of Firefox
-     * On Firefox 78 no event emitted when the user tries to delete pills.
-     * Therefore we need to fake what would normally happen
-     * @param direction in which to delete
-     * @returns handled
-     */
-    private fakeDeletion(backward: boolean): boolean {
-        const selection = document.getSelection();
-        // Use the default handling for ranges
-        if (selection.type === "Range") return false;
-
-        this.modifiedFlag = true;
-        const { caret, text } = getCaretOffsetAndText(this.editorRef.current, selection);
-
-        // Do the deletion itself
-        if (backward) caret.offset--;
-        const newText = text.slice(0, caret.offset) + text.slice(caret.offset + 1);
-
-        this.props.model.update(newText, backward ? "deleteContentBackward" : "deleteContentForward", caret);
-        return true;
-    }
-
     private async tabCompleteName(): Promise<void> {
         try {
             await new Promise<void>(resolve => this.setState({ showVisualBell: false }, resolve));