fix(selectfield,cheeckboxesfield): too much escaping

Signed-off-by: Thierry Bugier <tbugier@teclib.com>

Author: btry

inc/field/checkboxesfield.class.php

@@ -214,7 +214,6 @@ public function isValidValue($value): bool {
          return true;
       }
 
-      $value = Toolbox::stripslashes_deep($value);
       foreach ($value as $item) {
          if (trim($item) == '') {
             return false;

inc/field/selectfield.class.php

@@ -109,7 +109,6 @@ public function isValidValue($value): bool {
       if ($value == '0') {
          return true;
       }
-      $value = Toolbox::stripslashes_deep($value);
       $value = trim($value);
       return in_array($value, $this->getAvailableValues());
    }