exFilterColumn for type: 'date_custom_func' seems to have no effect on the filter

[louking]

test case: https://jsbin.com/cixawez/edit?html,js,output

steps to cause problem:

• load page -- ISO date for today should be in the filter (scroll to bottom of test case to see exFilterColumn invocation)

also ref: https://stackoverflow.com/questions/65460395/yadcf-clear-filter-when-using-date-custom-func-still-causes-last-date-to-be-supp

review of yadcf code shows exFilterColumn doesn't seem to have case for date_custom_func, which may be the root cause for this