release-22.1: sql: fix bug with multi-statement implicit txn schema changes and Bind

[blathers-crl]

Backport 1/1 commits from #92300 on behalf of @ajwerner.

/cc @cockroachdb/release

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For legacy reasons, we were resetting the descriptor collection state in Bind if we thought we were not in a transaction. Since #76792, we're always in a transaction. You might think that'd mean that the logic would not run. Sadly, for other still unclear reasons, when in an implicit transaction (*connExecutor).getTransactionState() returns NoTxnStateStr. The end result was that we'd erroneously reset our descriptor state in the middle of a multi- statement implicit transaction if bind was invoked.

Fixes #82921

Release note (bug fix): Fixed a bug which could lead to errors when running multiple schema change statements in a single command using a driver that uses the extended pgwire protocol internally (Npgsql in .Net as an example). These errors would have the form "attempted to update job for mutation 2, but job already exists with mutation 1".

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Release justification: bug fix

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

• Patches should only be created for serious issues or test-only changes.
• Patches should not break backwards-compatibility.
• Patches should change as little code as possible.
• Patches should not change on-disk formats or node communication protocols.
• Patches should not add new functionality.
• Patches must not add, edit, or otherwise modify cluster versions; or add version gates.

If some of the basic criteria cannot be satisfied, ensure that the exceptional criteria are satisfied within.

• There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
• The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
• New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters.
• The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.

Add a brief release justification to the body of your PR to justify this backport.

Some other things to consider:

• What did we do to ensure that a user that doesn’t know & care about this backport, has no idea that it happened?
• Will this work in a cluster of mixed patch versions? Did we test that?
• If a user upgrades a patch version, uses this feature, and then downgrades, what happens?

[cockroach-teamcity]

This change is