Adding retries interval to registry client

[robaiken]

What are you trying to accomplish?

Adding a retry interval to registry client Excon GET requests to better handle transient socket EOF errors affecting Maven and Terraform dependency updates by spacing out retry attempts.

Anything you want to highlight for special attention from reviewers?

The change spaces out retry attempts by 5 seconds, working with Excon's default of 4 retries for idempotent requests. This should help prevent rapid consecutive failures while still maintaining the existing retry behavior.

How will you know you've accomplished your goal?

• Error rate monitoring shows reduction in EOFError failures
• Failbot metrics confirm retried requests succeed

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.