Make stream_chat_persistence a add on dependency instead of shipping it with the llc

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

packages/stream_chat_persistence/lib/src/db/shared/unsupported_db.dart

@@ -11,7 +11,7 @@ class SharedDB {
 
   static constructOfflineStorage(
     String dbName, {
-    logStatements = false,
+    bool logStatements = false,
   }) {
     throw 'Unsupported Platform';
   }