Enable VSA deployment query modifications

What does this MR do?

This MR enables the query_deploymenys_via_finished_at_in_vsa (yes, typo) feature flag by default. The feature flag alters the deployments query (instead of filtering by created_at, we filter by finished_at).

The flag has been enabled on PRD and works as expected:

1. Go to: https://gitlab.com/groups/gitlab-org/-/analytics/value_stream_analytics
2. Deploys and Deployment Frequency values are using the new query.

• Related issue: #300649 (closed)
• FF was introduced here: !53050 (merged)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team