Accidentally marking paragraph field translatable creates big mess

We fell again into the old trap ourself. A paragraph field got marked as translatable.

Chances are pretty solid, this accidentally happens, because it is the default.

As a result, every language creates an own revision instead of a combined multilingual revision. Still the output looks fine in all translations. But data is a big mess.

If you later disable the field translation, the previous translation just disappears. You might see even "empty" revisions.

We should improve the storage to make sure, we can switch back and the data is still fine. This reduces big pain.

This is related to the official support for multilingual paragraph fields, but only needs a small fix compared to the full feature outlined in #2461695: Support asymmetric translations