Fixes JSONMatch issue in `insert` patches

Fixes a bug that caused insert patches with an after property where the JSONMatch expression provided matched multiple disjoint array elements (such as array[1, 3] or array[@ < 2].

Previously this lead to appending new items into the first region’s slot while pulling content from the last match, which dropped the first match and duplicated the last.

The patch now correctly inserts items so inserts land immediately after the last matched element.

This change affects all API versions - including v1 and all date-formatted versions