Allowed duplicates by not re-writing env vars for internal connection

[amp-powell]

…s if already used

Task name: CargoAuthenticateV0

Description: Checks if registry env var was used before over-writing it for an internal connection

Documentation changes required: (Y/N) N

Added unit tests: (Y/N) N

Attached related issue: (Y/N) Y - Task 2190999
Checklist:

• Task version was bumped - please check instruction how to do it
• Checked that applied changes work as expected