Even more space tweaks (#4588)

* Bring back the button to share a space on iOS 26.

* Remove the setting and disable the space tab on iOS 17.

(The tab bar is broken on iPadOS 17).

ElementX/Sources/Application/Settings/AppSettings.swift

@@ -61,7 +61,6 @@ final class AppSettings {
         case enableKeyShareOnInvite
         case knockingEnabled
         case threadsEnabled
-        case spacesEnabled
         case developerOptionsEnabled
         case nextGenHTMLParserEnabled
         case linkPreviewsEnabled
@@ -390,9 +389,6 @@ final class AppSettings {
     @UserPreference(key: UserDefaultsKeys.threadsEnabled, defaultValue: false, storageType: .userDefaults(store))
     var threadsEnabled
     
-    @UserPreference(key: UserDefaultsKeys.spacesEnabled, defaultValue: true, storageType: .userDefaults(store))
-    var spacesEnabled
-    
     @UserPreference(key: UserDefaultsKeys.nextGenHTMLParserEnabled, defaultValue: true, storageType: .userDefaults(store))
     var nextGenHTMLParserEnabled