Fix potentially invalid YAML outputs

Fixes invalid YAML caused by the combination of `?resolvePlaceholders=true` and `spring.cloud.config.server.encrypt.enabled = false`

Signed-off-by: Zachary Sistrunk <zachary@sistrunk.dev>

Author: zackman0010

spring-cloud-config-server/src/main/java/org/springframework/cloud/config/server/environment/EnvironmentController.java

@@ -228,6 +228,7 @@ public ResponseEntity<String> labelledYaml(@PathVariable String name, @PathVaria
 
 		if (resolvePlaceholders) {
 			yaml = resolvePlaceholders(prepareEnvironment(environment), yaml);
+			yaml = yaml.replaceAll(": \\{cipher}([0-9a-f]+)", ": '{cipher}$1'");
 		}
 
 		return getSuccess(yaml);