Customize or deactivate Group picker custom fields

Due to the bug below, the new functionality of New Global Issue Create modal uses a different way of searching groups inside Group picker custom fields:

• New Global Issue Create modal - Group picker fields search are case-sensitive

The group picker in the legacy Issue Create redirected users to a page to select the groups, while the new search introduced has the query attribute case-sensitive which may result in search results not showing up.

As a site/product administrator I would like to be able to customize the availability or fully deactivate the usage of those fields within the New Experience.