vmalert: remove notifier null check

[Haleygo]

, since -notifier.url is optional and is needed only if there are alerting rules.

https://new.docs.victoriametrics.com/vmalert/#topology-examples
-notifier.url is optional and is needed only if you have alerting rules.

Also vmalert has -notifier.blackhole flag which supports evaluating alerting rules without sending any notifications to external receivers (eg. alertmanager), see #811.
I think we can leave the check to vmalert itself.

Also, add minor sanity check for vmauth.
If vmauth.Spec.Ingress.TlsSecretName is used, vmauth.Spec.Ingress.TlsHosts is also needed according to the code, otherwise IngressRule will be illegal.

operator/controllers/factory/vmauth.go

Lines 413 to 425 in 9a481f2

	if cr.Spec.Ingress.TlsSecretName != "" {
	spec.TLS = []v12.IngressTLS{
	{
	SecretName: cr.Spec.Ingress.TlsSecretName,
	Hosts: cr.Spec.Ingress.TlsHosts,
	},
	}
	for _, host := range cr.Spec.Ingress.TlsHosts {
	hostRule := defaultRule.DeepCopy()
	hostRule.Host = host
	spec.Rules = append(spec.Rules, *hostRule)
	}
	} else {

[f41gh7]

LGTM