Learner: Single course ID returns string instead of array of string, causes WP_Query error

[jmalko]

Am submitting a PR, here's the issue:

Steps to Reproduce

1. Attempt to view a certificate
2. See type error within WP_Query

What I Expected

1. Wordpress expects the ['post__in'] arg to be an array

What Happened Instead

1. Sensei_Learner methods return a string in the case of looking at a single course

PHP / WordPress / Sensei LMS version

Wordpress 6.1
Sensei 4.10

Browser / OS version

Any

Screenshot / Video

[jmalko]

#6423

[donnapep]

@jmalko Thanks for the report! Unfortunately, I haven't been able to reproduce this error by viewing a certificate from either WP admin or on the frontend. Are there any additional details you could provide to enable us to reproduce it? Thx!