fix: stop retries from re-encoding path parameters

[RaphaelFakhri]

Why

build_path percent-encodes each value in the caller's path_params dict in place. The retry loop in _request_sync and _request_async passes the same kwargs, and therefore the same path_params dict, to every attempt. On the first attempt a value such as a b:c becomes a%20b%3Ac. On a retry the encoded value is encoded again and the request goes to a%2520b%253Ac, which addresses a different resource and typically returns a 404 instead of the result of the retried request.

The problem only appears when RetryConfig(enabled=True) is set, the request is a GET or HEAD, and a path parameter contains a character that quote escapes.

Changes

• build_path quotes the values into a new dict and leaves the caller's mapping unchanged.
• Add sync and async tests that retry a GET after a 429 and assert that both attempts request the same path.

Both new tests fail without the change (the second request uses a%2520b%253Ac) and pass with it.