fix: find query mongodb properly with @DeleteDateColumn()

[roseline124]

Description of change

Fixes #9250

Fix filterSoftDelted of MongoEntityManager not to reset query filter.
Previous version replaced cursor query filter with where this.deletedDateColumn.propertyName == null.
So there is a bug that the cursor queries all of not deleted data if the entity has DeletedDateColumn.

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• Code is up-to-date with the master branch
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[pleerock]

Thank you for contribution! 🎉

[serebro]

I have found a problem with current solution.

Let say I have three records in a collection users

[
    { "username" : "user1", "deletedAt" : null) },
    { "username" : "user2", "deletedAt" : ISODate("2023-09-02T18:26:48.253+0000") },
    { "username" : "user3" }
]

and Users entity

@Entity()
export class Users {
    @ObjectIdColumn()
    id: ObjectId

    @Column()
    username: string

    @DeleteDateColumn()
    deletedAt: Date
}

I make a query

const options = {
        where: {
            $or: [
                { username: { $regex: '^user' } },
            ]
        }
}
DataSource.manager.find(Users, options)

My query transforms by the current filterSoftDeleted function to this mongodb query

{
    $or: [
        { deletedAt: { $eq: null } },
        { username: { $regex: '^user' } },
    ]
}

As a result I receive all three records instead of two rows (one record "user2" is marked as deleted).
Expected result should be the following two records

[
    { "username" : "user1", "deletedAt" : null) },
    { "username" : "user3" }
]

It can be achieved by the following code

    protected filterSoftDeleted<Entity>(
        cursor: FindCursor<Entity>,
        deleteDateColumn: ColumnMetadata,
        query?: ObjectLiteral,
    ) {
        cursor.filter({...(query || {}), [deleteDateColumn.databasePath]: { $ne: {$type: 9} }});
    }