Summary

• MongoDB version 7.0.6
• MongoDB.Driver version 2.24

`is Array` condition translates in query string that doesn't work correct. Those string returns false when it must return true. 

!=null check is working by itself to determine if field is set. But when we use it in combined condition for array:
array!=null && array.Contains(`some_value`); in GroupBy method it leads to exception

How to Reproduce

I made a simple project that demonstrates few cases. Please find attached project below

Additional Background

I have a collection of documents that represents entity called Sirena in my program. And I needed to write the request that counts several parameters. Some of those fields are array, but In some documents this field is missing. As a result I faced the problem when I was trying to write a request to db.
I also posted a question on stackoverflow, I'm not sure if it may be useful, because attached project very carefully demonstrates the problems. One of users adviced me to use construction (array ?? long[]).Contains and it works. But I expect that `is Array` and `!=null` have to be translated to json query correct. 

The `is Array` condition translates to query string as:

```js
"$cond": {
    "if": {
        "$and": [{
                "$or": [

{                         "$eq": ["$some_array._t", "Array"]                     }

, {
                        "$and": [

{                                 "$isArray": "$some_array._t"                             }

,

{                                 "$in": ["Array", "$some_array._t"]                             }

                        ...

```
Unfortunately, if `some_array` field is array, condition `{"$eq": ["$some_array._t", "Array"]}` returns false. If we change it to `{"$isArray": "$some_array"}`, then it will works for array field. But as I see the second statement in 'or' condition has to work with field when it has several types. I don't know how to fix it.