Toggle import description with import_sources_enabled

What does this MR do?

• Toggles the description under New Project based on the import_sources_enabled flag

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

• Nope

Why was this MR needed?

• To avoid confusion in our instance where we do not have any import sources available

Screenshots (if relevant)

Before	After

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• 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 #34826 (closed)