register `TranslatorListener` service

Since the `TranslatorListener` was not registered as a service, the
proper locale would never have been passed from the current request
to the translator.
bug #12182 [FrameworkBundle] register `TranslatorListener` service (xabbuh)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[FrameworkBundle] register `TranslatorListener` service

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #12167
| License       | MIT
| Doc PR        |

Since the `TranslatorListener` was not registered as a service, the
proper locale would never have been passed from the current request
to the translator.

Commits
-------

3b578a6 register `TranslatorListener` service