Update call to post_exists to include post_type in the query

[dhusakovic]

During the post import we check whether the post already exists using post_exists.

The query currently utilises post title and date parameters, which will run through all the posts to try and find a match.

In cases where we have a large number of posts this query can time out and the import fail.

Passing the post_type to post_exists function allows us to use the type_status_date key, which significantly drops the number of rows examined and the overall query time in certain instances.

This change would also fix some edge case scenarios with posts across post types having the same title and date.

Issue link: #162

[dd32]

Per #162 this looks good to me.

The double-check on like 675 of get_post_type( $post_exists ) == $post['post_type'] should probably stay too, as it runs after a filter of this value.

[dhusakovic]

Hi @dd32 thanks for approving the PR! When can we expect this change to be merged?

[rebeccahum]

@dd32 Will this make it into 6.6 you think?