software/slapos-sr-testing: run ERP5 SR test with a python3 slapos.core

Now that "the bug in the way promises are run" referenced in the comment
in ${template:test} is being fixed, we can start running ERP5 with
python3 slapos.

software/slapos-sr-testing/software.cfg

@@ -337,6 +337,7 @@ tests =
   theia ${slapos.test.theia-setup:setup}
   metabase ${slapos.test.metabase-setup:setup}
   nginx-push-stream ${slapos.test.nginx-push-stream-setup:setup}
+  erp5 ${slapos.test.erp5-setup:setup}
 ###
   ${:extra}
 
@@ -345,7 +346,6 @@ extra =
 #          You should not add more lines here.
   backupserver ${slapos.test.backupserver-setup:setup}
   caddy-frontend ${slapos.test.caddy-frontend-setup:setup}
-  erp5 ${slapos.test.erp5-setup:setup}
   upgrade_erp5 ${slapos.test.upgrade_erp5-setup:setup}
   htmlvalidatorserver ${slapos.test.htmlvalidatorserver-setup:setup}
   slapos-master ${slapos.test.slapos-master-setup:setup}