Numbers can't be searched in default search - AfHER workaround

[SDScandrettKint]

In Arches 7, numbers can't be searched for in the default search. This is/was because numbers weren't being added to the terms index. This PR archesproject/arches#11623 fixes the issue, but it is targeted at 8.0 due to being a new feature rather than a bug fix.

If we want this feature in the 7.6 version of AfHER, we could extend the index?

This issue is relevant to AfHER, as users should be able to search PRNs in the default search. It is possible to do so in Advanced search, but that requires the knowledge of the resource model and is a few extra steps.