Search human readable names for property definitions

[thmsobrmlr]

When searching for an event property, we only consider the actual property name e.g. "$prev_pageview_duration" and not the human readable one e.g. "Previous pageview duration". In the example this leads to unexpected behaviour where the search doesn't show anything for anything more than "Prev".

Brief investigation shows that we handle the search backend side. There we only have the actual property names and the human readable ones are added in frontend side. We'd need to add them backend side an adapt the search accordingly.