Fix translation

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Have no clue why the BlockBundles translation is used for the translation in sonata-admin-blocks, but i got an error after the last `composer update` that the translation file can't be parsed, this PR fixes that problem.
That is really strange. I had in duplicated in my file. Did just an `composer update` and got an xml pareser error. Now i see that the original file is ok.