2.11.4 - Pass_Manager needs to check if highest pass ID exists before comparing

[ashleyfae]

Bug Report

Expected behavior

When I call Pass_Manager::hasPersonalPass() on a site that has no passes, I expect it to return false.

Actual behavior

The following exception is thrown:

InvalidArgumentException: Invalid pass 1:

The same is true for all other pass methods introduced in #8953

It just calls:

return self::pass_compare( $this->highest_pass_id, self::PERSONAL_PASS_ID, '=' );

But when $this->highest_pass_id is null, it doesn't work. We should be checking that before running the comparison.

Steps to reproduce the behavior

1. Have a site that has no passes activated.
2. Run any of the new helper methods.
3. Note exception error.

Information (if a specific version is affected):

PHP Version:

EDD Version (or branch): release/2.11.4

WordPress Version:

Any other relevant information: