[YAML] resolve variables in inlined YAML

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11665
| License       | MIT
| Doc PR        | 

#11569 does not resolve variables in inline YAML.
@tgabi333 Yeah, you're right. The warning has been fixed in #11843. Though a new Symfony version hasn't been released after the change has been merged.