fix(wait-strategy): close HTTPError in HttpWaitStrategy to avoid fd leak

[BrunosGits]

Summary

Fixes #1115: when an endpoint polled by HttpWaitStrategy answers with an error status, the raised HTTPError was never closed, leaking a file descriptor per poll (surfaces as ResourceWarning: Implicitly cleaning up <HTTPError ...> from tempfile.del).

Root cause

In _try_http_request, urlopen raises HTTPError for error statuses, so the with-block never owns it. The except arm forwards the error to _handle_http_error, which inspected error.code and returned without closing it. HTTPError wraps the response body fp, so each failed poll held an fd until GC.

Changes

• src/testcontainers/core/wait_strategies.py: _handle_http_error now closes the error in a finally block (isinstance-guarded, so the plain URLError path is untouched; the debug log runs before close).
• tests/core/test_wait_strategies.py: 2 regression tests - a Mock(spec=HTTPError) close assertion parametrized over unexpected/expected status codes, and a live 127.0.0.1 503-server behavioral check.

Testing

• New close assertions fail pre-fix (close called 0 times) and pass post-fix.
• tests/core/test_wait_strategies.py: 88 passed; tests/core/test_labels.py: 9 passed.
• ruff check + ruff format clean.

Closes #1115