[LLC] Fix search functions

Signed-off-by: Sahil Kumar <[email protected]>

packages/stream_chat/lib/src/extensions/map_extension.dart

@@ -0,0 +1,7 @@
+/// Useful extension functions for [Map]
+extension MapX on Map {
+  /// Returns a new map with null keys or values removed
+  Map<String, dynamic> get nullProtected {
+    return {...this}..removeWhere((key, value) => key == null || value == null);
+  }
+}