Add GCSToAzureBlobStorageOperator for GCS to Azure Blob transfer

[yuseok89]

Adds GCSToAzureBlobStorageOperator to copy objects from Google Cloud Storage to Azure Blob Storage.
There was no existing operator for this path (GCS → Azure Blob), so this fills that gap. The implementation follows the same overall patterns as S3ToAzureBlobStorageOperator.

Test Screenshots

Source files (GCS)

Default structure

Flatten structure

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[potiuk]

@yuseok89 This PR has been converted to draft because it does not yet meet our Pull Request quality criteria.

Issues found:

• ❌ Merge conflicts: this branch has conflicts with main and cannot be merged as-is. Rebase onto the current main to resolve: git fetch upstream main && git rebase upstream/main, resolve, force-push.

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• Rebase onto the current main to clear the merge conflicts.
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