feat(gax): implement queryStatusCallable for resumable uploads

[whowes]

This provides the ability for callers to query the server for the committed byte offset so far and detect if the upload has already finalized. This is needed for resumable uploads to be able to recover from occasional interruptions.

[gemini-code-assist]

Code Review

This pull request adds support for querying the status of an active resumable upload session by introducing QueryStatusRequest and QueryStatusResponse and implementing queryStatusCallable() in HttpJsonResumableUploadClient. Feedback on the changes highlights a critical issue where the client only accepts 2xx status codes for status queries, whereas Google's resumable upload protocol returns 308 Resume Incomplete for active uploads. The reviewer suggests updating the status check to accept 308 and adjusting the unit tests to use 308 instead of 200 for mock responses.

[sonarqubecloud]

Quality Gate passed for 'gapic-generator-java-root'

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
85.6% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[sonarqubecloud]

Quality Gate failed for 'gapic-generator-java-root'

Failed conditions
0.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud