Revert "Use the default mariadb container"

This reverts commit 7cc07e1.

Author: vmcj

.github/workflows/unit-tests.yml

@@ -9,14 +9,6 @@ on:
 
 jobs:
   check-static-codecov:
-    services:
-      sqlserver:
-        image: mariadb
-        ports:
-          - 3306:3306
-        env:
-          MYSQL_ROOT_PASSWORD: root
-        options: --health-cmd="healthcheck.sh --connect --innodb_initialized" --health-interval=10s --health-timeout=5s --health-retries=3
     container:
       image: domjudge/gitlabci:24.04
     runs-on: ubuntu-latest