storage: Renumber proposer-evaluated KV RaftCommand fields

Older versions were writing non-nil but empty values into these fields,
leading to problems on upgrade. Since there is no non-experimental use
of these fields yet, renumber them to discard all old data.

Fixes #10723

pkg/storage/storagebase/proposer_kv.proto

@@ -161,7 +161,7 @@ message RaftCommand {
   // TODO(tschottdorf): using an extra message here (and not just `bytes`) to
   // allow the generated RaftCommand to be compared directly. If
   // this costs an extra large allocation, we need to do something different.
-  optional WriteBatch write_batch = 10011;
+  optional WriteBatch write_batch = 10014;
 
-  reserved 1, 10001 to 10010, 10012;
+  reserved 1, 10001 to 10012;
 }