Hide the unread dot after previewing an invite. (#3800)

* Hide the unread dot when previewing an invite.

* Remove an invited room ID when accepting/rejecting.

* Remove the unread badge from knocked room cells.

* Update snapshots.

* Address PR comments.

Refactor KnockRequestType to JoinRequestType.

ElementX/Sources/Application/AppSettings.swift

@@ -20,6 +20,7 @@ protocol CommonSettingsProtocol {
 final class AppSettings {
     private enum UserDefaultsKeys: String {
         case lastVersionLaunched
+        case seenInvites
         case appLockNumberOfPINAttempts
         case appLockNumberOfBiometricAttempts
         case timelineStyle
@@ -104,6 +105,11 @@ final class AppSettings {
     @UserPreference(key: UserDefaultsKeys.lastVersionLaunched, storageType: .userDefaults(store))
     var lastVersionLaunched: String?
         
+    /// The Set of room identifiers of invites that the user already saw in the invites list.
+    /// This Set is being used to implement badges for unread invites.
+    @UserPreference(key: UserDefaultsKeys.seenInvites, defaultValue: [], storageType: .userDefaults(store))
+    var seenInvites: Set<String>
+    
     /// The default homeserver address used. This is intentionally a string without a scheme
     /// so that it can be passed to Rust as a ServerName for well-known discovery.
     private(set) var defaultHomeserverAddress = "matrix.org"