fix: `flutter_plugin` template generates all platforms no matter the platform flag used

[wolfenrain]

Description

As a developer I can create a flutter_plugin template using the CLI and pass which platforms I dont want using the --<platform_name> false option. This works as expected but the example generated for the plugin will still contain all platforms.

Steps To Reproduce

1. Run very_good create my_plugin -t flutter_plugin --ios false
2. Check the my_plugin/my_plugin/example directory, it will contain an iOS dir.

Expected Behavior

That the generated example only has the platforms that I require for my plugin.

[dewinjm]

The same goes with .github/workflows/ files.

When run for example very_good create abc_plugin -t flutter_plugin --web false --windows false --macos false --linux false

The workflows directory contains all platforms template and keep my_plugin files even though the plugin name is abc_plugin:

I see this file flutter_plugin_bundle.dart has the workflows static path. "my_plugin.yaml, my_plugin_android.yaml, ..."