hide invite avatars when such flag is on

This affects:
- Invited room preview inviter avatar
- Invited room preview room avatar
- Invited room cell inviter avatar in the room list
- Invited room cell room avatar in the room list
- Push notification for an invite

ElementX/Sources/Application/AppSettings.swift

@@ -12,6 +12,7 @@ import SwiftUI
 protocol CommonSettingsProtocol {
     var logLevel: LogLevel { get }
     var enableOnlySignedDeviceIsolationMode: Bool { get }
+    var hideInviteAvatars: Bool { get }
     var hideTimelineMedia: Bool { get }
     var eventCacheEnabled: Bool { get }
 }
@@ -40,6 +41,7 @@ final class AppSettings {
         case appAppearance
         case sharePresence
         case hideUnreadMessagesBadge
+        case hideInviteAvatars
         case hideTimelineMedia
         
         case elementCallBaseURLOverride
@@ -307,6 +309,9 @@ final class AppSettings {
     @UserPreference(key: UserDefaultsKeys.enableOnlySignedDeviceIsolationMode, defaultValue: false, storageType: .userDefaults(store))
     var enableOnlySignedDeviceIsolationMode
     
+    @UserPreference(key: UserDefaultsKeys.hideInviteAvatars, defaultValue: false, storageType: .userDefaults(store))
+    var hideInviteAvatars
+    
     @UserPreference(key: UserDefaultsKeys.hideTimelineMedia, defaultValue: false, storageType: .userDefaults(store))
     var hideTimelineMedia