implode not compatible with php8

[sfakir]

If I run your extension on php8 I get:

"implode(): Argument #2 ($array) must be of type ?array, string given"

According to (PHP docs implode)[https://www.php.net/manual/de/function.implode.php] needs to get the string value first, then the array.

// currently in code:
$grid .= implode(deserialize($arrGridClasses), ", "); 

// fix
$grid .= implode(", ", deserialize($arrGridClasses));

in GridClass.php Line 121; 149

euf_grid/classes/GridClass.php

Line 121 in a758742

$grid .= implode(deserialize($arrGridClasses), ", ");