release-25.4: sql: sort rulesForRelease versions in descending order

[celiala]

Backport 1/1 commits from #156374.

/cc @cockroachdb/release

---

This PR fixes incorrect ordering in the rulesForReleases array:

• Issue detected by claude-code-pr-review
• I verified via original PR that the array should be sorted in descending order.

Background

The rulesForReleases array in pkg/sql/schemachanger/scplan/plan.go stores schema changer rule registries for different cluster versions. The array is documented to be in descending order (newest version first), and the GetRulesRegistryForRelease() function depends on this ordering to correctly match cluster versions with their corresponding rule sets.

Bug

The array had V25_2 and V25_3 in ascending order instead of descending:

Before (incorrect):

var rulesForReleases = []rulesForRelease{
	{activeVersion: clusterversion.Latest, rulesRegistry: current.GetRegistry()},
	{activeVersion: clusterversion.V25_2, rulesRegistry: release_25_2.GetRegistry()},
	{activeVersion: clusterversion.V25_3, rulesRegistry: release_25_3.GetRegistry()},
}

After (correct):

var rulesForReleases = []rulesForRelease{
	// NB: sort versions in descending order, i.e. newest supported version first.
	{activeVersion: clusterversion.Latest, rulesRegistry: current.GetRegistry()},
	{activeVersion: clusterversion.V25_3, rulesRegistry: release_25_3.GetRegistry()},
	{activeVersion: clusterversion.V25_2, rulesRegistry: release_25_2.GetRegistry()},
}

Impact

GetRulesRegistryForRelease() iterates through the array in order and returns the first entry where activeVersion.IsActive() is true. With the incorrect ascending order, a cluster running version 25.3 would incorrectly get the 25.2 rules instead of the 25.3 rules.

Changes

• Fixed ordering in pkg/sql/schemachanger/scplan/plan.go
• Updated test expectations in pkg/cli/testdata/declarative-rules/invalid_version
• Regenerated test output in pkg/cli/testdata/declarative-rules/deprules

Epic: None
Release note (bug fix): Fix rulesForReleases ordering to correctly match cluster versions with schema changer rule sets.

Release justification: GetRulesRegistryForRelease() iterates through the array in order and returns the first entry where activeVersion.IsActive() is true. With the incorrect ascending order, a cluster running version 25.3 would incorrectly get the 25.2 rules instead of the 25.3 rules.

[blathers-crl]

Thanks for opening a backport.

Before merging, please confirm that the change does not break backwards compatibility and otherwise complies with the backport policy. Include a brief release justification in the PR description explaining why the backport is appropriate. All backports must be reviewed by the TL for the owning area. While the stricter LTS policy does not yet apply, please exercise judgment and consider gating non-critical changes behind a disabled-by-default feature flag when appropriate.

[cockroach-teamcity]

This change is 

[fqazi]

@celiala Thank you for doing this!

@fqazi reviewed 3 of 3 files at r1, all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @rafiss)