MongoDBPurger does not drop atlas search indexes

[pkowalski700lm]

Hello,

Issue encountered at version:1.6.7

After running doctrine:fixtures:load on mongodb database, where search indexes are defined on documents, search indexes are not dropped at all, just collections.
That leads to local database be in broken state, where after recreating collections search indexes with status DOES_NOT_EXIST appear.

It should first drop search indexes, and after that drop collections