Use EmojiDialog popup in chatbar

This converts the emoji dialog in the chatbar to be the same popup as for reactions. This includes:

- EmojiPicker and ReactionPicker were already similar and are made identical, as such ReactionPicker no longer needed
- Emoji dialog used for both reactions and chatbar emojis
- Add some parameters to allow for different use cases (include custom emojis and whether selection closes the popup)

![image](/uploads/c71bb5ffdc6914efad654998a886ade6/image.png)

src/qml/Page/RoomPage.qml

@@ -521,7 +521,7 @@ Kirigami.ScrollablePage {
                     onClicked: emojiDialog.open();
                     EmojiDialog {
                         id: emojiDialog
-                        onReact: {
+                        onChosen: {
                             page.currentRoom.toggleReaction(hoverActions.event.eventId, emoji);
                             chatBox.focusInputField();
                         }