remove references to wagtailadmin/shared/field_as_li.html

Changed all references from wagtailadmin/shared/field_as_li.html to
wagtailadmin/shared/field.html wrapped within li tags.

References:
https://docs.wagtail.org/en/stable/releases/5.1.html#shared-include-field-as-li-html-will-be-removed
4 jobs for master