Be more lenient with the power levels as they can still be missing at the time the various screens are created e.g. after accepting an invite.

The correct solution is to subscribe to update and update the UI accordingly when receiving them.

ElementX/Sources/Screens/RoomScreen/ComposerToolbar/CompletionSuggestionService.swift

@@ -19,10 +19,13 @@ private enum SuggestionTriggerRegex {
 final class CompletionSuggestionService: CompletionSuggestionServiceProtocol {
     private let roomProxy: JoinedRoomProxyProtocol
     private var canMentionAllUsers = false
+    
     private(set) var suggestionsPublisher: AnyPublisher<[SuggestionItem], Never> = Empty().eraseToAnyPublisher()
     
     private let suggestionTriggerSubject = CurrentValueSubject<SuggestionTrigger?, Never>(nil)
     
+    private var cancellables = Set<AnyCancellable>()
+    
     init(roomProxy: JoinedRoomProxyProtocol,
          roomListPublisher: AnyPublisher<[RoomSummary], Never>) {
         self.roomProxy = roomProxy
@@ -47,8 +50,14 @@ final class CompletionSuggestionService: CompletionSuggestionServiceProtocol {
                 self?.suggestionTriggerSubject.value != nil ? .milliseconds(500) : .milliseconds(0)
             }
         
-        guard let powerLevels = roomProxy.infoPublisher.value.powerLevels else { fatalError("Missing room power levels") }
-        canMentionAllUsers = powerLevels.canOwnUserTriggerRoomNotification()
+        roomProxy.infoPublisher
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] roomInfo in
+                self?.updateRoomInfo(roomInfo)
+            }
+            .store(in: &cancellables)
+        
+        updateRoomInfo(roomProxy.infoPublisher.value)
     }
     
     func processTextMessage(_ textMessage: String, selectedRange: NSRange) {
@@ -61,6 +70,12 @@ final class CompletionSuggestionService: CompletionSuggestionServiceProtocol {
     
     // MARK: - Private
     
+    private func updateRoomInfo(_ roomInfo: RoomInfoProxyProtocol) {
+        if let powerLevels = roomProxy.infoPublisher.value.powerLevels {
+            canMentionAllUsers = powerLevels.canOwnUserTriggerRoomNotification()
+        }
+    }
+    
     private func membersSuggestions(suggestionTrigger: SuggestionTrigger,
                                     members: [RoomMemberProxyProtocol],
                                     ownUserID: String) -> [SuggestionItem] {