fix: handle undefined record.id in List component (fixes #1678)

[diyorbekrustamjonov]

Fixes #1678

This PR fixes the TypeError: can't access property "toString", r.id is undefined error that occurs in the List component when BaseRecord.id() returns undefined or null.

Changes

• Added null/undefined check (r.id != null) before accessing id property
• Changed r.id.toString() to String(r.id) for safer type conversion
• Prevents error when filtering selected records from URL query parameters

Testing

• [x] Tested with custom adapters where id might be undefined
• [x] Verified backward compatibility with existing adapters
• [x] No breaking changes

Related Issues

Closes #1678