Strips multipart messages in BigQuery before comparing.

Co-authored-by: Anthonios Partheniou <partheniou@google.com>

* chore(main): release 3.1.1

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* Update CHANGELOG.md

---------

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>
Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: cojenco <cathyo@google.com>

…butes (#1449)

This change enhances observability by introducing these new features:

1. **Cloud Region Attribute**: The `cloud.region` attribute is now added
to all OpenTelemetry spans generated by the Spanner client. This
provides better geographical context for traces, aiding in performance
analysis and debugging across different regions.

2. **Transaction Tag**: The `transaction_tag` set on a `Transaction`
object is now correctly propagated and included in the `Commit` request.
This allows for better end-to-end traceability of transactions.

3. **Request Tag**: This introduces support for `request_tag` on
individual Spanner operations like `read`, `execute_sql`, and
`execute_update`. When a `request_tag` is provided in the
`request_options`, it is now added as a `spanner.request_tag` attribute
to the corresponding OpenTelemetry span. This allows for more granular
tracing and debugging of specific requests within a transaction or a
snapshot.

---------

Co-authored-by: surbhigarg92 <surbhigarg.92@gmail.com>

PR created by the Librarian CLI to initialize a release. Merging this PR will auto trigger a release.

Librarian Version: v1.0.0
Language Image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:8e2c32496077054105bd06c54a59d6a6694287bc053588e24debe6da6920ad91
<details><summary>google-cloud-spanner: 3.60.0</summary>

## [3.60.0](https://togithub.com/googleapis/python-spanner/compare/v3.59.0...v3.60.0) (2025-12-10)

### Features

* make built-in metrics enabled by default (#1459) ([64aebe7e](https://togithub.com/googleapis/python-spanner/commit/64aebe7e))

* Exposing AutoscalingConfig in InstancePartition ([8b6f1540](https://togithub.com/googleapis/python-spanner/commit/8b6f1540))

* add support for experimental host (#1452) ([9535e5e0](https://togithub.com/googleapis/python-spanner/commit/9535e5e0))

* enable OpenTelemetry metrics and tracing by default (#1410) ([bb5095df](https://togithub.com/googleapis/python-spanner/commit/bb5095df))

* add cloud.region, request_tag and transaction_tag in span attributes (#1449) ([d37fb80a](https://togithub.com/googleapis/python-spanner/commit/d37fb80a))

* Add QueryAdvisorResult for query plan (PiperOrigin-RevId: 832425466) ([e08260fe](https://togithub.com/googleapis/python-spanner/commit/e08260fe))

* Add Send and Ack mutations for Queues (PiperOrigin-RevId: 832425466) ([e08260fe](https://togithub.com/googleapis/python-spanner/commit/e08260fe))

* Add Spanner location API (#1457) (PiperOrigin-RevId: 833474957) ([e08260fe](https://togithub.com/googleapis/python-spanner/commit/e08260fe))

### Bug Fixes

* Deprecate credentials_file argument ([8b6f1540](https://togithub.com/googleapis/python-spanner/commit/8b6f1540))

* configure keepAlive time for gRPC TCP connections (#1448) ([efb2833e](https://togithub.com/googleapis/python-spanner/commit/efb2833e))

* Provide Spanner Option to disable metrics (#1460) ([f1ebc43b](https://togithub.com/googleapis/python-spanner/commit/f1ebc43b))

### Documentation

* Update description for the BatchCreateSessionsRequest and Session (PiperOrigin-RevId: 832425466) ([e08260fe](https://togithub.com/googleapis/python-spanner/commit/e08260fe))

* Update description for the IsolationLevel (PiperOrigin-RevId: 832425466) ([e08260fe](https://togithub.com/googleapis/python-spanner/commit/e08260fe))

</details>

* chore: add experimental blob properties tests

* include files

* fix

* fix mypy

* debug

* fix