Redact sensitive values from config in health data (#12421)

The health api returns the server configuration details. Redact
sensitive values from the config values like URLs and credentials.

internal/config/policy/opa/help.go

@@ -26,12 +26,14 @@ var (
 			Key:         URL,
 			Description: `[DEPRECATED] OPA HTTP(s) endpoint e.g. "http://localhost:8181/v1/data/httpapi/authz/allow"`,
 			Type:        "url",
+			Sensitive:   true,
 		},
 		config.HelpKV{
 			Key:         AuthToken,
 			Description: "[DEPRECATED] authorization token for OPA endpoint",
 			Optional:    true,
 			Type:        "string",
+			Sensitive:   true,
 		},
 		config.HelpKV{
 			Key:         config.Comment,