Refactor old cohort event selector

[mariusandra]

Changes

Removes something ancient.

Before:

After: (ignore the empty action in the list)

Other changes:

• Splits out TaxonomicStringPopup from TaxonomicPopup if you don't want to deal with a string | number type for all the onChange events. Makes things a bit easier.
• Adds the full-width class to the filter, because I kept adding a style='width:100%' tag to all new filters
• Creates a helper findActionName to find an action's name easily

How did you test this code?

Tried creating cohorts in the interface. Things worked. Hoping E2E tests also work.

[mariusandra]

Should have done reviews first... this was already done in:

• Definition Popups for all types of taxonomic filter groups! #8149