test(file-service): assert canonical child file URL in single-file collection

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

Author: vitormattos

tests/php/Unit/Service/FileServiceTest.php

@@ -549,5 +549,6 @@ public function testToArrayUsesSignerScopedSignRequestUuidForCurrentSignerUrl():
 		$this->assertIsArray($result['files']);
 		$this->assertCount(1, $result['files']);
 		$this->assertSame('file-uuid', $result['files'][0]['uuid']);
+		$this->assertSame('libresign.page.getPdf:file-uuid', $result['files'][0]['file']);
 	}
 }