fix(files): Bulk insert file blob indexes during assembly

[sentry]

This PR addresses an N+1 query issue in AbstractFile.assemble_from_file_blob_ids.

Problem:
Previously, the assemble_from_file_blob_ids method iterated over file_blobs and called self._create_blob_index(blob=blob, offset=offset) for each blob individually. This resulted in N separate INSERT queries into the sentry_fileblobindex table for a file composed of N blobs, leading to significant performance overhead, especially for large files with many chunks.

This N+1 pattern affected tasks such as assemble_preprod_artifact_installable_app, assemble_artifacts, and assemble_dif.

Solution:

1. An abstract method _bulk_create_blob_indexes was added to AbstractFile.
2. Concrete implementations of _bulk_create_blob_indexes were provided in File and ControlFile, utilizing FileBlobIndex.objects.bulk_create and ControlFileBlobIndex.objects.bulk_create respectively.
3. The assemble_from_file_blob_ids method was refactored:
   • It now first pre-computes all (blob, offset) pairs in a single pass.
   • Then, it calls _bulk_create_blob_indexes once, performing a single batch INSERT query for all FileBlobIndex records.
   • Finally, it iterates through the blobs again to stream their contents to a temporary file and compute the checksum.

This change reduces the database operations from N individual INSERTs to a single bulk_create call, significantly improving performance for file assembly operations.

Verification:

• ruff check src/sentry/models/files/abstractfile.py src/sentry/models/files/file.py src/sentry/models/files/control_file.py passed successfully.
• Automated tests for tests/sentry/tasks/test_assemble.py, tests/sentry/models/test_file.py, and tests/sentry/preprod/test_tasks.py should be run in CI to confirm full functionality, as the local sandbox environment does not support running the full test suite.

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Fixes SENTRY-5QZ3

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