Date filter doesn't apply default offset values

Problem/Motivation

While developing a datetime Better Exposed Filter (#3500976: Build a DatetimePicker plugin to also handle time ), I noticed that the default offset value was not applied when no value was submitted.

I tried to use hooks like hook_views_pre_view(), hook_views_pre_execute() but acceptExposedInput() was always overriding the value $handler->value['value'] to null

Steps to reproduce

Proposed resolution

If the filter was not submitted but has default offset values, apply them so backends receive resolved dates.

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet