fix(storage): Invocation ID is not retained on multipart upload retries

[thiyaguk09]

Hoists the generation of persistentInvocationId to the beginning of the
upload process in Bucket.upload and File.save. This ensures that retried multipart upload attempts reuse the same invocation ID in the x-goog-api-client header, rather than generating a new one for each attempt.

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Fixes #<issue_number_goes_here> 🦕

[gemini-code-assist]

Code Review

This pull request implements persistent invocationId tracking across the upload lifecycle and refactors the StorageTransport.makeRequest method to improve project ID resolution and header management. Feedback focuses on critical issues in the makeRequest refactor, including a bug where the request body is incorrectly assigned to an undefined property, thread-safety risks from unconditionally clearing shared interceptors, and an inconsistent response handler that mutates data and breaks return type expectations.