The way test submission works changed significantly when we switched
to using the lava_runner. In that change set, I preserved the logic
around when the submit tasks ran, such that they only ran when a valid
LAVA configuration existed in the job variables, and when the pipeline
is not for a merge request.

In repository preceding those changes, there was a valid LAVA
configuration, but the test submission was given `--dry-run` so that
we would run our templating, but stop short of submitting the jobs,
even though we required a valid LAVA configuration to exist.

In the repository after these changes, there is not a valid LAVA
configuration (since the required variables changed) and now the test
generation step is no longer occurring on pipelines. Moreover, if we
made the LAVA configuration valid for the state we have now, it would
both generate and run the tests, because the generation and run steps
have identical rules governing them in CI.

Therefore, remove the checks for a valid LAVA configuration from the
generation step. This means we do not need a valid LAVA configuration
in order to get the same behaviour we had before: generate the tests,
but do not submit them.