Using 'fields' in Bucket.exists().

This prepares the way for using the `query_and_wait` method built-in to the client library when available.

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- [ ] Make sure to open an issue as a [bug/issue](https://togithub.com/googleapis/python-bigquery-pandas/issues/new/choose) before writing your code!  That way we can discuss the change, evaluate designs, and agree on the general idea
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Towards #710 
🦕

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>

Removing @googleapis/api-logging, @googleapis/api-logging-partners, and
@googleapis/api-logging-reviewers. Replaced with
@googleapis/yoshi-python in metadata and blunderbuss.

b/476446922

Source-Link: googleapis/synthtool@d2871d9
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:b2dc5f80edcf5d4486c39068c9fa11f7f851d9568eea4dcba130f994ea9b5e97

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

* feat: enable SQLAlchemy 2.0's insertmany feature

- Enable the use_insertmanyvalues flag on the dialect to support
  SQLAlchemy 2.0's insertmany feature, which allows multiple ORM
  objects to be inserted together in bulk, even if the table has
  server-side generated values which must be included in a THEN RETURN
  clause
- Provide an example for using the feature with client-side supplied
  UUIDs and insert_sentinel columns.
- Ensure that the feature is not enables for bit-reversed primary
  keys. In other dialects, an incrementing primary key can be used
  rather than a sentinel column. In Spanner, the bit-reversed integers
  do not meet the ordering requirement to be used as implicit
  sentinels

https://docs.sqlalchemy.org/en/20/core/internals.html#sqlalchemy.engine.default.DefaultDialect.use_insertmanyvalues

https://docs.sqlalchemy.org/en/20/core/connections.html#insert-many-values-behavior-for-insert-statements

https://docs.sqlalchemy.org/en/20/core/connections.html#configuring-sentinel-columns

Fixes: #720

* chore: update tests for multiplexed sessions

* chore: make sample runnable

* fix: exclude commit_timestamp col from THEN RETURN

---------

Co-authored-by: Knut Olav Løite <koloite@gmail.com>

* tests: add retry conf s7 resumable upload test cases

* adjust fixture and chunk size from design discussion