Core - Cancel pending tasks when browser crashed or v8 context gets released

[campersau]

Fixes: #5144

Summary:

• Pending tasks from EvaluateScriptAsync are now being canceled when the V8Context gets released / the browser crashes / the browser gets disposed.

Changes:

• Storing pending tasks per frame (e.g. V8Context) instead of just globally, this makes it possible to cancel them

How Has This Been Tested?
Unittest

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Updated documentation

Checklist:

• Tested the code(if applicable)
• Commented my code
• Changed the documentation(if applicable)
• New files have a license disclaimer
• The formatting is consistent with the project (project supports .editorconfig)

Summary by CodeRabbit

• Bug Fixes

  • Script evaluations now surface clear exceptions when the browser/host or frame is unavailable; pending evaluations are reliably canceled on crashes, disposals, navigation, or context changes.

• New Features

  • Pending JavaScript tasks are scoped per frame, allowing targeted cancellation and improved isolation.

• Tests

  • New tests for evaluation/callback cancellation on context changes and crashes, plus repeated callback execution.

• Refactor

  • Internal task management reorganized for frame-based storage and more robust timeout/cancellation handling.