omit accept-encoding from upload

[shubhangi-google]

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closes: #<issue_number_goes_here>

[gemini-code-assist]

Code Review

This pull request refactors the handling of the Accept-Encoding: gzip header, moving it from a global service-level configuration to a specific per-request header for downloads. This change prevents potential parsing errors during file uploads where gzipped metadata might be returned. The PR includes updated documentation, new acceptance tests, and modified unit tests to verify the header's behavior. Feedback was provided to avoid in-place mutation of the options hash to prevent potential FrozenError exceptions.

[shubhangi-google]

/gemini review

[gemini-code-assist]

Code Review

This pull request modifies the google-cloud-storage library to move the Accept-Encoding: gzip header from a global request option to a specific option for file downloads. This ensures that the header is omitted during file uploads while maintaining it for downloads. The changes include updates to the service initialization, the download_file method, documentation, and a comprehensive set of unit and acceptance tests to verify the new behavior. I have no feedback to provide.