[CIVIS-11753] FIX prevent infinite recursion in retry logic when Retry-After header is missing

[mattyb]

The retry_request function was repeatedly wrapping the wait strategy each time it was called with the same retrying object. Since APIClient reuses a single tenacity.Retrying instance across all API calls, this created deeply nested wait_for_retry_after_header wrappers. When the API returned an error without a Retry-After header, the fallback chain would recurse infinitely, exceeding Python's recursion limit.

The fix adds a guard to only wrap the wait strategy once, preserving the intended behavior: use Retry-After when present, otherwise fall back to the user's configured wait strategy (exponential backoff by default).

Added test that simulates 1000 consecutive API calls to verify the fix.

🤖 Generated with Claude Code

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