Include multidisciplinary tag in tag filters

[suecarmol]

Description

Include the multidisciplinary_tag when filtering by other tags.

Rationale

Since multidisciplinary collections may have content by which that tag is filtered, they should be included in the filter.

Phabricator Ticket

T289253

How Has This Been Tested?

Added test cases on existing cases.

Manual testing:

1. Go to My Library
2. Filter the collections by a tag
3. Check that the collections are filtered by that tag and that multidisciplinary collections are also included

Screenshots of your changes (if appropriate):

Results when filtering by History tag

Types of changes

What types of changes does your code introduce? Add an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Minor change (fix a typo, add a translation tag, add section to README, etc.)

[suecarmol]

@Samwalton9 I think this PR can also be merged with your review (it's a fairly straightforward change).

[Samwalton9]

This looks good to me and I sorted my local environment out so I could test locally and it seems to be working as intended!