remove platform specific plugin configuration & allow to change text height from client code

[alexmercerind]

Hey! Thanks for the awesome package for showing lyrics inside Flutter.

Only "plugins" need to have platform specific code for leveraging native functionalities through platform interface.
Since, this "package" only aims to provide non-platform specific UI only code, there is no need to create platform specific configuration with native code for each platform.
This results in unnecessary bundling of shared libraries on all platforms, which isn't even used.

More details may be found at: https://docs.flutter.dev/development/packages-and-plugins/developing-packages#types

I also removed hardcoded copyWith calls which change the rendered Text's height to 1. I don't know if this results in some problem, sure let me know.

[ozyl]

Thank you for your PR. After removing the platform configuration, the only supported platform on the pub is WEB. It was also because of this that these configurations were added before. I don't know the reason, can you help?
➡️：pub link

[alexmercerind]

Thanks for letting met know!

fluent_ui also doesn't have any declared platform specific code, but on pub.dev it shows that it supports all platforms, how a package should.

I think we should add this at the end of pubspec.yaml (see: here) & remove fluttr_web_plugins from dependencies:

flutter:
  uses-material-design: true

I generally only work on plugins or non-UI FFI packages, so I didn't have much knowledge about this.

Thanks again! And sorry for breaking it.

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I have raised #19 to save your time & incremented version too.