[TwigBundle] Adds service check for extension loading

This PR adds following checks:
*  `twig.extension.form` extension is loaded if `form.extension` service is defined
*  `twig.extension.trans` extension is loaded if `translator` service is defined

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #6238