loadbalancer: don't assume IPv4 IP address on load balancer

The azure load balancer resource's frontend_ip_configuration argument assumes
the IP address is only going to be IPv4. This removes that restriction to be
in line with the rest of the terraform code that does not have that validation.

https://bugzilla.redhat.com/show_bug.cgi?id=1808973

azurerm/internal/services/network/resource_arm_loadbalancer.go

@@ -81,10 +81,9 @@ func resourceArmLoadBalancer() *schema.Resource {
 						},
 
 						"private_ip_address": {
-							Type:         schema.TypeString,
-							Optional:     true,
-							Computed:     true,
-							ValidateFunc: validate.IPv4AddressOrEmpty,
+							Type:     schema.TypeString,
+							Optional: true,
+							Computed: true,
 						},
 
 						"private_ip_address_version": {