Update example port in Geo registry docs to 5050

What does this MR do?

Since version 12.5, Registry is enabled by default on port 5050 when Let's Encrypt integration is used. This MR updates the docuemntations example port configuration to port 5050 instead of 4567 to avoid confusion with users setting up Docker Registry for a Geo secondary node when Registry is enabled by default on the primary.

Related issues

Created MR !32780 (merged) also to update the configuration on when Container Registry is not enabled by default to use port 5050 as well isntead of 4567.

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