bump mockito to version 5.4.1 (#4085)

Part of flutter/flutter#127226

Follow up to flutter/packages#3544. Version 5.4.0 from that PR is not new enough, see

```
Because mockito >=5.4.0 <5.4.1 depends on test_api >=0.2.1 <0.6.0 and every version of flutter_test from sdk depends on test_api 0.6.0, mockito >=5.4.0 <5.4.1 is incompatible with flutter_test from sdk.
So, because quick_actions_platform_interface depends on both flutter_test from sdk and mockito 5.4.0, version solving failed.
```

https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8780090492483790881/+/u/run_test.dart_for_flutter_plugins_shard_and_subshard_analyze/test_stdout

Author: christopherfujino

google_maps_flutter_platform_interface/pubspec.yaml

@@ -21,4 +21,4 @@ dev_dependencies:
   async: ^2.5.0
   flutter_test:
     sdk: flutter
-  mockito: 5.4.0
+  mockito: 5.4.1

google_maps_flutter_web/example/pubspec.yaml

@@ -25,4 +25,4 @@ dev_dependencies:
   http: ^0.13.0
   integration_test:
     sdk: flutter
-  mockito: 5.4.0
+  mockito: 5.4.1