Move "hasMCU" update to the top of the method

"hasMCU" was used before being updated, so this caused an unneeded call
to "getPeersForCall" when processing the users in the room for the first
time even if the MCU is actually used.

A better fix might be moving "hasMCU" to a method instead of relying on
the cached value, but just moving the update to the top of the method
should have no side effects (as calling "getPeersForCall" just updates
"participantMap", which is unused when the MCU is used, and sets the
avatars, which has no effect until the peer layout is set, which also
sets the avatar), so this is good enough for now.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>

app/src/main/java/com/nextcloud/talk/controllers/CallController.java

@@ -1655,6 +1655,8 @@ public class CallController extends BaseController {
         List<String> newSessions = new ArrayList<>();
         Set<String> oldSesssions = new HashSet<>();
 
+        hasMCU = hasExternalSignalingServer && webSocketClient != null && webSocketClient.hasMCU();
+
         for (HashMap<String, Object> participant : users) {
             if (!participant.get("sessionId").equals(callSession)) {
                 Object inCallObject = participant.get("inCall");
@@ -1693,8 +1695,6 @@ public class CallController extends BaseController {
             getPeersForCall();
         }
 
-        hasMCU = hasExternalSignalingServer && webSocketClient != null && webSocketClient.hasMCU();
-
         for (String sessionId : newSessions) {
             getPeerConnectionWrapperForSessionIdAndType(sessionId, "video", hasMCU && sessionId.equals(webSocketClient.getSessionId()));
         }