Fix behaviour of 'when filter empty' for empty and notEmpty filter types.

[samwho]

Description

Originally discovered while investigating #13583, because empty and notEmpty filters are passed like so to the search endpoint:

// request rows where `someKey` is empty
{ empty: { someKey: null } }

// request rows where `someKey` is not empty
{ notEmpty: { someKey: null } }

The allFiltersEmpty variable in packages/backend-core/src/db/lucene.ts does not get set to false when these are the only filters in the search, a check prevents it.

To fix this, I'm making certain allFiltersEmpty is set to false when these filters are present, and I have added new tests to ensure this behaviour does not regress.

Addresses

• https://linear.app/budibase/issue/BUDI-8232/is-empty-filter-condition-causes-no-rows-to-be-returned-if-when-filter

Launchcontrol

Fix some confusing behaviour when you perform a search that only contains an empty or notEmpty filter, and you have set the "when filter empty" to "none". Previously, "when filter empty: none" could cause searches to return no rows when there were filters present. This is no longer the case.