Fix - Prevent TypeError in CheckboxesField::regex() when stored value is invalid JSON

[RomainLvr]

Changes description

Checklist

Please check if your PR fulfills the following specifications:

• Tests for the changes have been added
• Docs have been added/updated

Description

• It fixes !44948
• Here is a brief description of what this PR does

When rendering the plugin_formcreator_solved_issues dashboard widget, a TypeError is thrown:

preg_grep(): Argument #2 ($array) must be of type array, null given

This happens when a form answer contains a checkbox field with a regex visibility condition, and the stored JSON value is corrupted or invalid. json_decode() returns null on invalid input, leaving $this->value = null, which then causes preg_grep() to throw.

A secondary bug was also found in LdapselectField::regex(), which incorrectly used preg_grep() on a plain string value instead of preg_match().

Changes

• CheckboxesField::deserializeValue(): add is_array() guard after json_decode() so $this->value always ends up as an array, even when the stored data is malformed. This mirrors the existing pattern in ActorField.
• LdapselectField::regex(): replace preg_grep() with preg_match(), consistent with RadiosField which holds a single string value.
• tests/CheckboxesField.php: add testRegex() covering valid match, no match, invalid JSON, and JSON-null cases.