feat(dart): add dart config to very_good.yaml

[unicoderbot]

Add support for VeryGoodDartConfig configuration in the very_good.yaml file to customize defaults for the very_good dart test command.

Changes

• Added VeryGoodDartConfig and VeryGoodDartTestConfig classes to support dart-specific configuration
• Updated DartTestCommand.run() to load and apply configuration from very_good.yaml
• Modified DartTestOptions.parse() to accept a VeryGoodConfig parameter and resolve argument values with proper precedence: CLI args > config values > CLI defaults
• Added _resolveArg() helper function to handle argument resolution with fallback values
• Updated error handling to catch and report VeryGoodConfigParseException
• Added comprehensive tests for configuration parsing and precedence
• Updated documentation with dart test configuration examples

Configuration Precedence

Argument values are resolved in the following order:

1. Command line arguments (highest priority)
2. Values from very_good.yaml configuration
3. CLI default values (lowest priority)

Closes #1655

[ryzizub]

LGTM

[marcossevilla]

@vgvbot merge main into this PR, solve the conflicts that come up

[unicoderbot]

On it, I'll merge the target branch into this PR and resolve any conflicts.

• Preparing environment
  • Cloning repository
  • Setting up dev environment
• Fetching target branch
• Merging target into PR
• Updating PR branch

I merged main into this PR and resolved the conflicts.