Previously, these endpoints required `service:write` permission on _any_
service as a sort of proxy for "is the caller allowed to participate in
the mesh?".
Now, they're called as part of the process of establishing a server
connection by any consumer of the consul-server-connection-manager
library, which will include non-mesh workloads (e.g. Consul KV as a
storage backend for Vault) as well as ancillary components such as
consul-k8s' acl-init process, which likely won't have `service:write`
permission.
So this commit relaxes those requirements to accept *any* valid ACL token
on the following gRPC endpoints:
- `hashicorp.consul.dataplane.DataplaneService/GetSupportedDataplaneFeatures`
- `hashicorp.consul.serverdiscovery.ServerDiscoveryService/WatchServers`
- `hashicorp.consul.connectca.ConnectCAService/WatchRoots`
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