[CI] Add failing when config contains errors or not found

This change voids hanging on waiting for SSH connections.
Status code signal last error, so checking status after redirecting stream to sed
affects previous status emitted by python command.

Author: KFilipek

.github/workflows/qemu.yml

@@ -85,7 +85,8 @@ jobs:
       run: qemu-img resize ./ubuntu-23.04-server-cloudimg-amd64.img +4G
     - name: Print qemu args
       run: |
-        echo `python3 scripts/qemu/qemu_config.py scripts/qemu/configs/${{matrix.config}}.xml | sed s/''\''/'/g`
+        # notice: should be sedded, but it hides status
+        python3 scripts/qemu/qemu_config.py scripts/qemu/configs/${{matrix.config}}.xml
     - name: Run qemu
       run: |
         sudo qemu-system-x86_64 \