swapUser method
Function to swap AgoraUser in the floating layout.
Implementation
void swapUser({required int index}) {
final AgoraUser newUser = value.users[index];
final AgoraUser tempAgoraUser = value.mainAgoraUser;
value = value.copyWith(mainAgoraUser: newUser);
addUser(callUser: tempAgoraUser);
removeUser(uid: newUser.uid);
}