Describe the bug

Warning in ./libraries/classes/ConfigStorage/Relation.php#449
Undefined array key 0 when browsing a table with complex foreign keys
(e.g. Shopware 6 product table).

Steps to reproduce

1. Have a Shopware 6 database on MariaDB 10.11
2. Open phpMyAdmin and browse the product table (SELECT * FROM product)
3. Warning appears immediately

Root cause

In Relation.php around line 449, the parser result is accessed without a null check:

// BEFORE (broken):
$stmt = $parser->statements[0];

When PhpMyAdmin\SqlParser\Parser fails to parse Shopware 6's complex
SHOW CREATE TABLE product output (due to long constraint chains and
self-referencing foreign keys), it returns an empty statements[] array.
Accessing [0] on an empty array triggers the warning.

The instanceof CreateStatement check below already guards the usage
of $stmt, but not the assignment.

Fix

// AFTER (fixed):
$stmt = $parser->statements[0] ?? null;

This is safe because the existing instanceof CreateStatement check
handles null gracefully, leaving foreign_keys_data as [].

Server configuration

• phpMyAdmin version: 5.2.3
• MariaDB version: 10.11.11-MariaDB-0+deb12u1 (Debian 12)
• PHP version: PHP 8.3.6
• Web server: nginx version: nginx/1.24.0 (Ubuntu)

Additional context

Shopware 6's product table has ~15+ foreign keys including
self-referencing ones (parent_id → id), which appear to cause the
SqlParser to return an empty statements[] instead of throwing an exception.

Verified fix works on phpMyAdmin 5.2.1 and 5.2.3.