cmd/k8s-operator: allow HA ingresses to be deleted when VIP service does not exist (#18050)

This commit fixes a bug in our HA ingress reconciler where ingress resources would
be stuck in a deleting state should their associated VIP service be deleted within
control.

The reconciliation loop would check for the existence of the VIP service and if not
found perform no additional cleanup steps. The code has been modified to continue
onwards even if the VIP service is not found.

Fixes: https://github.com/tailscale/tailscale/issues/18049

Signed-off-by: David Bond <davidsbond93@gmail.com>

cmd/k8s-operator/api-server-proxy-pg_test.go

@@ -182,9 +182,7 @@ func TestAPIServerProxyReconciler(t *testing.T) {
 	expectEqual(t, fc, certSecretRoleBinding(pg, ns, defaultDomain))
 
 	// Simulate certs being issued; should observe AdvertiseServices config change.
-	if err := populateTLSSecret(t.Context(), fc, pgName, defaultDomain); err != nil {
-		t.Fatalf("populating TLS Secret: %v", err)
-	}
+	populateTLSSecret(t, fc, pgName, defaultDomain)
 	expectReconciled(t, r, "", pgName)
 
 	expectedCfg.AdvertiseServices = []string{"svc:" + pgName}
@@ -247,9 +245,7 @@ func TestAPIServerProxyReconciler(t *testing.T) {
 	expectMissing[rbacv1.RoleBinding](t, fc, ns, defaultDomain)
 
 	// Check we get the new hostname in the status once ready.
-	if err := populateTLSSecret(t.Context(), fc, pgName, updatedDomain); err != nil {
-		t.Fatalf("populating TLS Secret: %v", err)
-	}
+	populateTLSSecret(t, fc, pgName, updatedDomain)
 	mustUpdate(t, fc, "operator-ns", "test-pg-0", func(s *corev1.Secret) {
 		s.Data["profile-foo"] = []byte(`{"AdvertiseServices":["svc:test-pg"],"Config":{"NodeID":"node-foo"}}`)
 	})