Simplify disk space cleanup step condition

Remove conditional check for Ubuntu in disk space cleanup step.

(cherry picked from commit 02c7f74)

Author: hfmehmed

.github/workflows/auto-merge.yml

@@ -19,7 +19,6 @@ jobs:
 
     steps:
       - name: Free Disk Space (Ubuntu)
-        if: matrix.os == 'ubuntu-latest'
         run: |
           echo "Disk space before cleanup:"
           df -h