feat(policy): classify signature flow as value choice

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

lib/Service/Policy/Provider/Signature/SignatureFlowPolicy.php

@@ -49,6 +49,7 @@ public function get(string|\BackedEnum $policyKey): IPolicyDefinition {
 					return $rawValue;
 				},
 				appConfigKey: self::SYSTEM_APP_CONFIG_KEY,
+				resolutionMode: PolicySpec::RESOLUTION_MODE_VALUE_CHOICE,
 			),
 			default => throw new \InvalidArgumentException('Unknown policy key: ' . $this->normalizePolicyKey($policyKey)),
 		};