Alerting: Collate rule_group column as binary (#114365)

* fix: collate rule_group column as utf8mb4_bin

This ensures this column is sorted identically by the database and
golang, which should eliminate issues related to a mismatch in sort
order.

* chore: make test stricter

* fix: also add binary collation for postgres

pkg/services/sqlstore/migrations/migrations.go

@@ -162,4 +162,6 @@ func (oss *OSSMigrations) AddMigration(mg *Migrator) {
 	ualert.ExpandAlertRuleUpdatedByMigration(mg)
 
 	ualert.AddAlertRuleGroupIndexMigration(mg)
+
+	ualert.CollateBinAlertRuleGroup(mg)
 }