feat(metrics): anonymous access when enabled in accessControl config (#4110)

* feat: add anonymouspolicy support in metrics

Signed-off-by: uaggarwa <uaggarwa@akamai.com>

* test: add unit tests

Signed-off-by: uaggarwa <uaggarwa@akamai.com>

---------

Signed-off-by: uaggarwa <uaggarwa@akamai.com>

pkg/cli/server/root.go

@@ -793,8 +793,10 @@ func validateAuthzPolicies(config *config.Config, logger zlog.Logger) error {
 
 	logger.Info().Msg("checking if anonymous authorization is the only type of authorization policy configured")
 
+	// if no authentication is configured, policies must be anonymous-only;
 	if !authConfig.IsBasicAuthnEnabled() && !config.IsMTLSAuthEnabled() && !authConfig.IsBearerAuthEnabled() &&
-		!accessControlConfig.ContainsOnlyAnonymousPolicy() {
+		!accessControlConfig.ContainsOnlyAnonymousPolicy() &&
+		!accessControlConfig.ContainsOnlyMetricsAnonymousPolicy() {
 		msg := "access control config requires one of htpasswd, ldap, openid or mTLS authentication " +
 			"or using only 'anonymousPolicy' policies"
 		logger.Error().Err(zerr.ErrBadConfig).Msg(msg)