fingerprint: only log failed Consul fingerprint once (#25182)

In #24526 we updated Consul and Vault fingerprinting so that we no longer
periodically fingerprint. In #25102 we made it so that we fingerprint
periodically on start until the first fingerprint, in order to tolerate Consul
or Vault not being available on start. For clusters not running Consul, this
leads to a warn-level log every 15s. This same log exists for Vault, but Vault
support is opt-in via `vault.enable = true` whereas you have to manually disable
the fingerprinter for Consul.

Make it so that we only log a failed Consul fingerprint once per Consul
cluster. Reset the gate on this once we have a successful fingerprint, so that
we get the logs after a reload if Consul is unavailable.

Ref: #24526
Ref: #25102
Fixes: #25181

client/fingerprint/consul.go

@@ -55,6 +55,10 @@ type consulState struct {
 	// tracks that we've successfully fingerprinted this cluster at least once
 	// since the last Fingerprint call
 	fingerprintedOnce bool
+
+	// we currently can't disable Consul fingerprinting, so for users who aren't
+	// using it we want to make sure we report the periodic failure only once
+	reportedOnce bool
 }
 
 // valueReader is used to parse out one attribute from consulInfo. Returns
@@ -225,9 +229,15 @@ func (cfs *consulState) query(logger hclog.Logger) agentconsul.Self {
 	// If we can't hit this URL consul is probably not running on this machine.
 	info, err := cfs.client.Agent().Self()
 	if err != nil {
+		if cfs.reportedOnce {
+			return nil
+		}
+		cfs.reportedOnce = true
 		logger.Warn("failed to acquire consul self endpoint", "error", err)
 		return nil
 	}
+
+	cfs.reportedOnce = false
 	return info
 }