Adjust chat button in call view
Adjust chat button in call view

Replace icon with MessageText when in call.
Counter bubble now lets hover and click through.
Display two notifications when mentionned.

Signed-off-by: Vincent Petry <87e1f221a672a14a323e57bb65eaea19d3ed3804@nextcloud.com>

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed