[FrameworkBundle] adds --clean option translation:update command

This PR adds `--clean` option to `translation:update` command.
This options activates unused translation removal.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #6592