Add Maestro tests for create & join rooms (#472)

I created 2 additional test users to use them as MXID we lookup during room creation.

I.e. we will not login as those users, it's just 2 known MXIDs that we know exist so we can look them up.

- https://github.com/vector-im/element-x-android/issues/409

.github/workflows/maestro.yml

@@ -50,4 +50,6 @@ jobs:
             USERNAME=maestroelement
             PASSWORD=${{ secrets.MATRIX_MAESTRO_ACCOUNT_PASSWORD }}
             ROOM_NAME=MyRoom
+            INVITEE1_MXID=@maestroelement2:matrix.org
+            INVITEE2_MXID=@maestroelement3:matrix.org
             APP_ID=io.element.android.x.debug