release-22.1: pgwire: Add support for cursors with special characters

[rimadeodhar]

Backport 1/1 commits from #85859.

/cc @cockroachdb/release

---

IIn CockroachDB and Postgres, it is possible to declare
cursors with special characters enclosed within double
quotes, for e.g. "1-2-3". Currently, we store the name
as an unescaped string which causes problems during the
pgwire DESCRIBE step for looking up the cursor. We should
be storing using the tree.Name datatype for the cursor name
while storing and looking up cursors. This PR updates the code
to start using tree.Name instead of raw strings for handling
cursor names. This fixes the issue where the pgwire DESCRIBE
step fails while attempting to look up cursors with names
containing special characters.

Resolves #84261

Release note (bug fix): The pgwire DESCRIBE step no longer
fails with an error while attempting to look up cursors
declared with names containing special characters.

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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