Make Boolean descriptions consistent

What does this MR do?

Rewrite some of the Boolean field descriptions to be more consistent with the standard agreed upon in this comment - Booleans framed in terms of "what does this field do" i.e. Indicates repository has a Git repository

We can't edit the pagination descriptions as they seem to be part of graphql-ruby. I think that's okay though, since it's a good description.

Screenshots

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

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

Related to #31645 (closed)