Hook up client pausing and resuming next to sync starting and stopping for nightly and debug builds.

This will hopefully close all file descriptors and prevent the system from killing the app in the background.
Reported in https://github.com/matrix-org/matrix-rust-sdk/issues/6366 and implemented in https://github.com/matrix-org/matrix-rust-sdk/pull/6495

ElementX/Sources/Application/Settings/AppSettings.swift

@@ -81,6 +81,7 @@ final class AppSettings {
         case focusEventOnNotificationTap
         case linkNewDeviceEnabled
         case automaticBackPaginationEnabled
+        case clientPausingAndResumingEnabled
         
         // Doug's tweaks 🔧
         case roomListActivityVisibility
@@ -448,6 +449,9 @@ final class AppSettings {
     @UserPreference(key: UserDefaultsKeys.automaticBackPaginationEnabled, defaultValue: false, storageType: .userDefaults(store))
     var automaticBackPaginationEnabled
     
+    @UserPreference(key: UserDefaultsKeys.clientPausingAndResumingEnabled, defaultValue: appBuildType != .release, storageType: .volatile)
+    var clientPausingAndResumingEnabled
+    
     @UserPreference(key: UserDefaultsKeys.developerOptionsEnabled, defaultValue: appBuildType != .release, storageType: .userDefaults(store))
     var developerOptionsEnabled
 }