[v9]: Bump Dart and Flutter version, Dart to 3.5.0, Flutter to 3.24.0

[denrase]

📜 Description

• Bump dart and flutter min versions
• Remove dynamic casts for unavailable APIs
• Format

💡 Motivation and Context

Closes #2626

💚 How did you test it?

CI

📝 Checklist

• I reviewed submitted code
• I added tests to verify changes
• No new PII added or SDK only sends newly added PII if sendDefaultPii is enabled
• I updated the docs if needed
• All tests passing
• No breaking changes

[github-actions]

🚨 Detected changes in high risk code 🚨

High-risk code has higher potential to break the SDK and may be hard to test. To prevent severe bugs, apply the rollout process for releasing such changes and be extra careful when changing and reviewing these files:

• flutter/lib/src/screenshot/recorder.dart

[buenaflor]

looks good on first pass 👍

will have another look later

[buenaflor]

we have another library added now link, you can change the versions there too

[ueman]

You can also get rid of this compatibility code:

sentry-dart/flutter/lib/src/event_processor/flutter_enricher_event_processor.dart

Lines 274 to 279 in a24a1db

	/// Copied from https://api.flutter.dev/flutter/services/appFlavor-constant.html
	/// As soon as Flutter 3.16 is the minimal supported version of Sentry, this
	/// can be replaced with the property from the link above.
	const String? _appFlavor = String.fromEnvironment('FLUTTER_APP_FLAVOR') != ''
	? String.fromEnvironment('FLUTTER_APP_FLAVOR')
	: null;

[codecov]

Codecov Report

Attention: Patch coverage is 91.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 89.17%. Comparing base (79ccefb) to head (adef8af).
Report is 200 commits behind head on v9.

Files with missing lines	Patch %	Lines
...nt_processor/flutter_enricher_event_processor.dart	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##               v9    #2643       +/-   ##
===========================================
+ Coverage   67.94%   89.17%   +21.22%     
===========================================
  Files          15      263      +248     
  Lines         443     8924     +8481     
===========================================
+ Hits          301     7958     +7657     
- Misses        142      966      +824     

☔ View full report in Codecov by Sentry.
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[vaind]

LGTM

[vaind]

Suggested change

	- Bump Dart and Flutter version, Dart to 3.5.0, Flutter to 3.24.0 ([#2643](https://github.com/getsentry/sentry-dart/pull/2643))
	- Increase minimum SDK version requirements to Dart v3.5.0 and Flutter v3.24.0 ([#2643](https://github.com/getsentry/sentry-dart/pull/2643))