cli: Add node_prefix read policy to Consul setup task policy. (#25310)

When Nomad registers a service within Consul it is regarded as a
node service. In order for Nomad workloads to read these services,
it must have an ACL policy which includes node_prefix read. If it
does not, the service is filtered out from the result.

This change adds the required permission to the Consul setup
command.

.changelog/25310.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+cli: Add node_prefix read when setting up the task workload identity Consul policy
+```

command/asset/consul-wi-default-policy.hcl

@@ -1,3 +1,7 @@
+node_prefix "" {
+  policy = "read"
+}
+
 service_prefix "" {
   policy = "read"
 }