feat(flutter-web): improve stackframes

[buenaflor]

:scroll: Description

Depends on https://github.com/getsentry/sentry-dart-plugin/pull/319

:bulb: Motivation and Context

Cleans up the stacktrace to make them cleaner and easier to look at by stripping the verbose prefixes.

Closes https://linear.app/getsentry/issue/DART-112/flutter-web-improve-stackframe-ui

:green_heart: How did you test it?

plugin test

Before

After

:pencil: Checklist

• [ ] I reviewed submitted code
• [ ] I added tests to verify changes
• [ ] I updated the docs if needed
• [ ] All tests passing
• [ ] No breaking changes

:crystal_ball: Next steps