kvserver: move maybeRefreshProposals to own method

Allows the use of deferred unlock.

Release note: None

Part of: cockroachdb#105366

pkg/kv/kvserver/replica_raft.go

@@ -1141,11 +1141,7 @@ func (r *Replica) handleRaftReadyRaftMuLocked(
 	if r.store.TestingKnobs().EnableUnconditionalRefreshesInRaftReady {
 		refreshReason = reasonNewLeaderOrConfigChange
 	}
-	if refreshReason != noReason {
-		r.mu.Lock()
-		r.refreshProposalsLocked(ctx, 0 /* refreshAtDelta */, refreshReason)
-		r.mu.Unlock()
-	}
+	r.maybeRefreshProposals(ctx, refreshReason)
 
 	// NB: if we just processed a command which removed this replica from the
 	// raft group we will early return before this point. This, combined with
@@ -1199,6 +1195,14 @@ func (r *Replica) handleRaftReadyRaftMuLocked(
 	return stats, nil
 }
 
+func (r *Replica) maybeRefreshProposals(ctx context.Context, refreshReason refreshRaftReason) {
+	if refreshReason != noReason {
+		r.mu.Lock()
+		defer r.mu.Unlock()
+		r.refreshProposalsLocked(ctx, 0 /* refreshAtDelta */, refreshReason)
+	}
+}
+
 // asyncReady encapsulates the messages that are ready to be sent to other peers
 // or to be sent to local storage routines when async storage writes are enabled.
 // All fields in asyncReady are read-only.