build: go 1.24

We were running behind and there were quite some deprecations to update.
This was mostly in the upstream copy/pasta package but seems quite
minimal.

vendor/google.golang.org/grpc/internal/balancer/gracefulswitch/gracefulswitch.go

@@ -109,8 +109,9 @@ func (gsb *Balancer) switchTo(builder balancer.Builder) (*balancerWrapper, error
 		return nil, errBalancerClosed
 	}
 	bw := &balancerWrapper{
-		builder: builder,
-		gsb:     gsb,
+		ClientConn: gsb.cc,
+		builder:    builder,
+		gsb:        gsb,
 		lastState: balancer.State{
 			ConnectivityState: connectivity.Connecting,
 			Picker:            base.NewErrPicker(balancer.ErrNoSubConnAvailable),
@@ -293,6 +294,7 @@ func (gsb *Balancer) Close() {
 // State updates from the wrapped balancer can result in invocation of the
 // graceful switch logic.
 type balancerWrapper struct {
+	balancer.ClientConn
 	balancer.Balancer
 	gsb     *Balancer
 	builder balancer.Builder
@@ -413,7 +415,3 @@ func (bw *balancerWrapper) UpdateAddresses(sc balancer.SubConn, addrs []resolver
 	bw.gsb.mu.Unlock()
 	bw.gsb.cc.UpdateAddresses(sc, addrs)
 }
-
-func (bw *balancerWrapper) Target() string {
-	return bw.gsb.cc.Target()
-}