Allow multiple select of areas for search filter

Make sure you have solr setup and working, with Page, Assign, and Forum search areas enabled ( https://docs.moodle.org/dev/Global_search ) Create a course, and in the course, create a page with title Page, assign with title Assign, and Forum with title Forum. For each, put FindMe in the description. Index site content Search for FindMe Confirm you get results for Page, Assign, and Forum In the filter section, click the dropdown, and select Page Search Confirm you only get a result for Page In the filter section, click the dropdown, and select Forum (now you have Page and Forum selected) Search Confirm you only get results for Page and Forum In the filter section, click the dropdown, and select Assign (now you have Page, Assign, and Forum selected) Search Confirm you get results for Page, Assign, and Forum In the filter section, click to remove forum Search Confirm you only get results for Page and Assign In the filter section, remove Page and Assign Search Confirm you get results for Page, Assign, and Forum