Disable the "request access" functionality by default for new groups and projects

What does this MR do?

Changes the default value of the "request_access_enabled column for both groups and projects. Thanks to @MrChrisW for the original MR in !7011 (closed)

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Currently this feature is enabled by default, and additional action is required to disable it.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #21992 (closed) Closes !7011 (closed)