fix: add support for extracted activities in git integration v2

[mbani01]

Changes proposed ✍️

This pull request enhances the commit activity extraction and processing logic in the Git integration service, particularly in how activities are parsed from commit messages and prepared for downstream processing. It also includes a minor formatting update to the settings configuration.

Commit activity extraction and processing improvements:

• The create_activities_from_commit method now processes activities extracted from the commit message (e.g., "Signed-off-by") and generates corresponding activity records, ensuring that these are included alongside standard commit activities. Extracted activity types are normalized to match legacy conventions (e.g., "signed-off-commit"), and unique source IDs are generated for each extracted activity.
• The return value of create_activities_from_commit has been updated to a tuple containing both database and queue activity lists, clarifying the method's output and supporting downstream processing.

Configuration and formatting:

• Improved formatting for the REPOSITORY_UPDATE_INTERVAL_HOURS environment variable assignment in settings.py for better readability.

Checklist ✅

• Label appropriately with Feature, Improvement, or Bug.
• Add screenshots to the PR description for relevant FE changes
• New backend functionality has been unit-tested.
• API documentation has been updated (if necessary) (see docs on API documentation).
• Quality standards are met.