PHPORM-369: Fix ID handling when using insert method instead of save

[alcaeus]

PHPORM-369

Checklist

• Add tests and ensure they pass

This addresses an issue highlighted in a discussion about rename_embedded_id_field: when using DB::table()->insert, we pass $values directly to aliasIdForQuery. Since $values contains a list of documents at this point, every document is treated as an embedded document and misses out on the ID handling for root documents. To work around this, we call aliasIdForQuery on each document through array_map.
I also added a test with a model that has $incrementing set to false, as the wrong behaviour is bypassed when $incrementing is its default true value.

[jmikola]

I noted in #3428 (comment) you mentioned that $incrementing = true (Eloquent's default per Primary Keys) was responsible for a different code path being utilized.

Assuming this library is going to generate ObjectIds regardless, I would think it'd be ideal if $incrementing had absolutely no effect on our behavior. Is this something we have no control over (within reason)?

[jmikola]

Noted that this goes back to Illuminate\Database\Eloquent\Model::performInsert().

When $incrementing is true, Model::insertAndSetId() relies on Builder::insertGetId() (where $values appears to be a single document). Otherwise, it delegates to Builder::insert(), which has the logic to wrap the singular document in an array before applying aliasIdForQuery().

So the bug fix looks correct. I think there's still an edge case in the "document or documents?" detection within Builder::insert(), but that' outside the scope of this PR. This assumption could be problematic if all fields in a document were arrays (e.g. _id is an embedded document):

As soon as we find a value that is not an array we assume the user is inserting a single document.