Backport of Remove log line about server mgmt token init into release/1.14.x (#15612)

Co-authored-by: freddygv <freddy@hashicorp.com>

.changelog/15610.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+acl: avoid debug log spam in secondary datacenter servers due to management token not being initialized.
+```

agent/consul/acl_server.go

@@ -116,7 +116,6 @@ func (s *serverACLResolverBackend) IsServerManagementToken(token string) bool {
 		return false
 	}
 	if mgmt == "" {
-		s.logger.Debug("server management token has not been initialized")
 		return false
 	}
 	return subtle.ConstantTimeCompare([]byte(mgmt), []byte(token)) == 1