fix(amazonq): fix for /test project payload collection filter

[ashishrp-aws]

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Description

For both the /test and /review agents, we parse files by looping through each module to ensure all files from the project/workspace are included. The current common utility, FeatureDevSessionContext, is focused on loading the .gitignore file from the project root. While this works in most cases, for internal Amazon workspaces with multiple packages loaded into the same workspace, the .gitignore files are not being loaded to filter out irrelevant files.
Even the default patterns in the utility are not working because each file is checked for the relative path from the project root, which is derived from IntelliJ's utility function guessProjectDir(). This function may provide one of the modules as the root, but that is not always the case, causing the relative path check to fail.

• Decoupled the gitignore logic as seperate class (/dev and /review can also onboard to this class with the same utility of featureDevSessionContext)
• Added unit tests with tests for gitignore in multi module workspaces.

Checklist

• My code follows the code style of this project
• I have added tests to cover my changes
• A short description of the change has been added to the CHANGELOG if the change is customer-facing in the IDE.
• I have added metrics for my changes (if required)

License

I confirm that my contribution is made under the terms of the Apache 2.0 license.