fix(web): Error: "@staticInterop" classes should not contain any generative constructors

[JonasJW]

Description

This PR fixed a build error described here: #1378

It changes all external ... with external factory in packages/audioplayers_web/lib/web_audio_js.dart, as described in this issue flutter/flutter#115988

Checklist

• The title of my PR starts with a Conventional Commit prefix (fix:, feat:, docs:, chore: etc).
• I have read the Contributor Guide and followed the process outlined for submitting PRs.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation and added dartdoc comments with ///, where necessary.
• I have updated/added relevant examples in example.

Note: only minor changes that don't require updating tests, docs or example

Breaking Change

• Yes, this is a breaking change.
• No, this is not a breaking change.

Related Issues

Fixes #1378

[spydon]

Lgtm, but I have no idea what consequences this has.

[Gustl22]

Thank you @JonasJW !

[FeodorFitsner]

Any chance you could publish a new version of audioplayers package sooner? Flutter 3.7 is out and a project compilation is failing. Thank you!

[spydon]

Any chance you could publish a new version of audioplayers package sooner? Flutter 3.7 is out and a project compilation is failing. Thank you!

Done! audioplayers 3.0.0 is released :)

[FeodorFitsner]

Wow, that was fast! 🚀 Thank you very much!

Can confirm I'm able to build project with Flutter 3.7 now.