fix: await aiohttp server handler on collector-address skip (#423)

Await the original RequestHandler._handle_request when an HTTP request
matches the collector address. Previously, the skip path returned the
function object, causing aiohttp to fail when unpacking the response.

Preserve argument forwarding and skip Entry-span creation for collector
requests. Add regression coverage for the skip path and verify that
non-collector requests still create an Entry span.

Update dorny/paths-filter from v4.0.1 to the Apache-approved v4.0.3 SHA
to unblock CI startup.

Validation:
- All five HTTP reporter unit tests pass locally.
- The new skip-path regression test fails without the handler fix.
- Workflow validation passes; full CI results are pending.