Do not run buildstream test suite in the containers used to run the testsuite

This is already done in buildstream CI itself

Also, the bst-test test run wherever is in buildstream master at the point CI runts, so things can break without a chance to fix them on this repo

Of course, this is a trade-off between having known-to-work images and spending CI time verifying it in this repo. But I think is worth as they will be tested in the buildstream repo anyway and we can fix them if something is wrong when try to use in there

Also, with current situation we verify in here with the latest buildstream from master when the CI run, so we can not fix CI in here, which is what is happening now with Fedora 43 test job has started to fail (#59 - closed) • Unassigned, for example)