fix: the test change username

onchain/src/tests/username_store.cairo

@@ -26,20 +26,14 @@ fn test_change_username() {
     let contract_address = deploy_contract();
     let dispatcher = IUsernameStoreDispatcher { contract_address };
 
-    //let simulated_caller_address = contract_address;
-
-    // Claim initial username
     let initial_username = 'devsweet';
     dispatcher.claim_username(initial_username);
 
-    // Verify initial claim
+    //get user address
     let initial_username_address = dispatcher.get_username(initial_username);
 
-    //assert_eq!(initial_username_address, simulated_caller_address, "Initial username not claimed properly");
-
-    // Claim a new username for changing
+    //a new username for changing
     let new_username = 'devcool';
-    dispatcher.claim_username(new_username);
 
     // Change to a new, different username
     dispatcher.change_username(new_username);