sql: prevent tables with PARTITION BY clauses from becoming multi-region

[otan]

Release justification: low-risk update to new functionality
Release note: None

Refs #59719

[cockroach-teamcity]

This change is 

[ajstorm]

Reviewed 2 of 2 files at r1.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @otan)

---

pkg/sql/alter_database.go, line 593 at r1 (raw file):

		return pgerror.Newf(
			pgcode.ObjectNotInPrerequisiteState,
			"cannot convert table %s to a multi-region table as it has PARTITION BY defined",

Nit: Do we want to make this a Newf with details? Thinking that the top-line error message should be "cannot convert database %q to a multi-region database", with details "cannot convert table %s...".

also, instead of "as it has PARTITION BY defined", do we just want to say "as it is partitioned"?

---

pkg/sql/alter_database.go, line 601 at r1 (raw file):

			return pgerror.Newf(
				pgcode.ObjectNotInPrerequisiteState,
				"cannot convert table %s to a multi-region table as it has index/constraint %s with PARTITION BY defined",

Nit: Same comments as above (details, "...defined")

[otan]

done!

bors r=ajstorm

[craig]

Build succeeded:

• GitHub CI (Cockroach)