Use Symfony Request for fieldui module

Part of #1998638: [Meta] Refactor raw PHP variables (e.g $_SERVER, $_REQUEST, $_GET, $_POST) with Symfony Request object

Files that need converting are:

• core/modules/field_ui/field_ui.admin.in
• core/modules/field_ui/lib/Drupal/field_ui/FieldOverview.php
• core/modules/field_ui/lib/Drupal/field_ui/Form/FieldInstanceEditForm.php