Element Call permission tweaks (#2187)

* vector-im/element-meta/issues/2230 - Specify `call.member` default power levels when creating a room

* vector-im/element-meta/issues/2229 - Take into account permissions when configuring the room screen call button

ElementX/Sources/Screens/RoomScreen/RoomScreenModels.swift

@@ -129,6 +129,7 @@ struct RoomScreenViewState: BindableState {
 
     var ownUserID: String
     
+    var canJoinCall = false
     var hasOngoingCall = false
     
     var bindings: RoomScreenViewStateBindings

ElementX/Sources/Screens/RoomScreen/RoomScreenViewModel.swift

@@ -115,6 +115,13 @@ class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol
         // Note: beware if we get to e.g. restore a reply / edit,
         // maybe we are tracking a non-needed first initial state
         trackComposerMode(.default)
+        
+        Task {
+            let userID = roomProxy.ownUserID
+            if case let .success(permission) = await roomProxy.canUserJoinCall(userID: userID) {
+                state.canJoinCall = permission
+            }
+        }
     }
     
     // MARK: - Public

ElementX/Sources/Screens/RoomScreen/View/RoomScreen.swift

@@ -162,6 +162,7 @@ struct RoomScreen: View {
         if !ProcessInfo.processInfo.isiOSAppOnMac {
             ToolbarItem(placement: .primaryAction) {
                 callButton
+                    .disabled(context.viewState.canJoinCall == false)
             }
         }
     }