release-23.2: sql: sort overload functions according to search_path

[blathers-crl[bot]]

Backport 1/1 commits from #126281 on behalf of @XiaochenCui.

/cc @cockroachdb/release

---

Previously, overload functions were not sorted based on the "search_path", and the "PreferredOverload" attribute makes the sorting doesn't make sense, causing issue #124538.

This commit addresses these issues by:

• Introducing sorting logic in the "combineOverloads" function and including a search_path argument to ensure overloaded functions are returned in the correct order.

• Resetting the "PreferredOverload" attribute of overloaded functions to "false" when user-defined functions are present, so the type-checking routine selects overloaded functions based on their order.

• Only throw "ambiguous error" for user-defined functions.

Users can now override built-in functions using "search_path".

Replaces: https://github.com/cockroachdb/cockroach/pull/126048 Fixes: #124538

Release note (bug fix): Fixed a bug where a user-defined function that shared a name with a builtin function would not be resolved, even if it had higher precedence from the search_path variable.

---

Release justification: bug fix

[blathers-crl[bot]]

Thanks for opening a backport.

Please check the backport criteria before merging:

• [ ] Backports should only be created for serious issues or test-only changes.
• [ ] Backports should not break backwards-compatibility.
• [ ] Backports should change as little code as possible.
• [ ] Backports should not change on-disk formats or node communication protocols.
• [ ] Backports should not add new functionality (except as defined here).
• [ ] Backports must not add, edit, or otherwise modify cluster versions; or add version gates.
• [ ] All backports must be reviewed by the owning areas TL and one additional TL. For more information as to how that review should be conducted, please consult the backport policy.

If your backport adds new functionality, please ensure that the following additional criteria are satisfied:

• [ ] 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. State changes must be further protected such that nodes running old binaries will not be negatively impacted by the new state (with a mixed version test added).
• [ ] The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.
• [ ] Your backport must be accompanied by a post to the appropriate Slack channel (#db-backports-point-releases or #db-backports-XX-X-release) for awareness and discussion.

Also, please add a brief release justification to the body of your PR to justify this backport.

[cockroach-teamcity]

This change is 

[XiaochenCui]

I will review the failed tests later.

[rafiss]

I will review the failed tests later.

Thanks, but no need. There's a known issue with that failing job, which is why it's not marked as "Required."