Remove deprecated usages of mongodb and mongoose `remove`, `update`, and `insert` methods (#16573)
* Remove usage of mongo .insert in favour of .insertOne
* Replace usages of update with updateOne
* Replace remove with deleteOne/deleteMany
* Update one more usage of `remove`
* Update a few missed usages of remove/update/insert
GitOrigin-RevId: 49d08eca1ce80831c375c343fb8b5b3846b71460