CHECK constraint not shown in UI

[Emaxoso]

Adminer version: 5.4.1
Compiled: single file (downloaded from adminer.org)
Driver: MySQL / MariaDB
Database version: 12.1.2-MariaDB
Plugins used: none

The CHECK constraint exists in the database, but it is not shown in the Adminer UI.

Steps to reproduce

CREATE TABLE `test` (
  `a` int,
  `b` int
);

ALTER TABLE `test`
  ADD CONSTRAINT `test_constraint`
  CHECK (a IS NOT NULL);

Expected result
The constraint test_constraint should be visible in the Adminer interface.

I suspect this line may be responsible: here

[Emaxoso]

I tried removing the line mentioned above and the CHECK constraints became visible again in the UI.
I would be happy to open a PR, but I’m not sure what impact this change could have on PostgreSQL support