mma: convert kvpb.ReplicationChanges to a single change per store

Previously, a VOTER => NON_VOTER transition, or vice versa, was producing
multiple changes for a store, which is invalid according to the contract
of PendingRangeChange. This is now fixed by changing the logic in
mmaintegration.convertReplicaChangeToMMA, and adding a
mmaprototype.MakeReplicaTypeChange function.

Informs #157049

Epic: CRDB-55052

Release note: None

Author: sumeerbhola

pkg/BUILD.bazel

@@ -276,6 +276,7 @@ ALL_TESTS = [
     "//pkg/kv/kvserver/logstore:logstore_test",
     "//pkg/kv/kvserver/loqrecovery/loqrecoverypb:loqrecoverypb_test",
     "//pkg/kv/kvserver/loqrecovery:loqrecovery_test",
+    "//pkg/kv/kvserver/mmaintegration:mmaintegration_test",
     "//pkg/kv/kvserver/multiqueue:multiqueue_test",
     "//pkg/kv/kvserver/print:print_test",
     "//pkg/kv/kvserver/protectedts/ptcache:ptcache_test",
@@ -1596,6 +1597,7 @@ GO_TARGETS = [
     "//pkg/kv/kvserver/loqrecovery:loqrecovery",
     "//pkg/kv/kvserver/loqrecovery:loqrecovery_test",
     "//pkg/kv/kvserver/mmaintegration:mmaintegration",
+    "//pkg/kv/kvserver/mmaintegration:mmaintegration_test",
     "//pkg/kv/kvserver/multiqueue:multiqueue",
     "//pkg/kv/kvserver/multiqueue:multiqueue_test",
     "//pkg/kv/kvserver/print:print",

pkg/kv/kvserver/allocator/mmaprototype/allocator_state.go

@@ -832,7 +832,7 @@ func (a *allocatorState) AdjustPendingChangeDisposition(change PendingRangeChang
 	// state. We gather the found changes.
 	var changes []*pendingReplicaChange
 	for _, c := range change.pendingReplicaChanges {
-		ch, ok := a.cs.pendingChanges[c.ChangeID]
+		ch, ok := a.cs.pendingChanges[c.changeID]
 		if !ok {
 			continue
 		}
@@ -849,9 +849,9 @@ func (a *allocatorState) AdjustPendingChangeDisposition(change PendingRangeChang
 	}
 	for _, c := range changes {
 		if success {
-			a.cs.pendingChangeEnacted(c.ChangeID, a.cs.ts.Now())
+			a.cs.pendingChangeEnacted(c.changeID, a.cs.ts.Now())
 		} else {
-			a.cs.undoPendingChange(c.ChangeID)
+			a.cs.undoPendingChange(c.changeID)
 		}
 	}
 }