feat: Add support for isFederate option for rooms

lib/src/client.dart

@@ -790,6 +790,7 @@ class Client extends MatrixApi {
     HistoryVisibility? historyVisibility,
     bool waitForSync = true,
     bool groupCall = false,
+    bool federated = true,
     Map<String, dynamic>? powerLevelContentOverride,
   }) async {
     enableEncryption ??=
@@ -824,6 +825,7 @@ class Client extends MatrixApi {
     }
 
     final roomId = await createRoom(
+      creationContent: federated ? null : {'m.federate': false},
       invite: invite,
       preset: preset,
       name: groupName,

lib/src/room.dart

@@ -1347,6 +1347,10 @@ class Room {
   @Deprecated('Use fullyRead marker')
   String? get userFullyReadMarker => fullyRead;
 
+  bool get isFederated =>
+      getState(EventTypes.RoomCreate)?.content.tryGet<bool>('m.federate') ??
+      true;
+
   /// Sets the position of the read marker for a given room, and optionally the
   /// read receipt's location.
   /// If you set `public` to false, only a private receipt will be sent. A private receipt is always sent if `mRead` is set. If no value is provided, the default from the `client` is used.

test/room_test.dart

@@ -778,6 +778,19 @@ void main() {
       expect(timeline.events.length, 17);
     });
 
+    test('isFederated', () {
+      expect(room.isFederated, true);
+      room.setState(
+        StrippedStateEvent(
+          type: EventTypes.RoomCreate,
+          content: {'m.federate': false},
+          senderId: room.client.userID!,
+          stateKey: '',
+        ),
+      );
+      expect(room.isFederated, false);
+    });
+
     test('getUserByMXID', () async {
       final List<String> called = [];
       final List<String> called2 = [];