heptapod-ci: always make the default run condition explicit This has no effect on behavior, it's just to make everything obvious.

heptapod-ci: remove push exception for named branches The internal workings of Heptapod cause even fast-forward merges to look like pushes to Gitlab. The only way to run a pipeline on topic-less named branches is not through the web interface. I am probably the only person affected by this, so it's not really a problem. This was confirmed with Georges, the maintainer of Heptapod, though the only way to be *actually* sure, is to merge this and see.

heptapod-ci: (hopefully) fix the pipeline savings system There is no easy way for me to test this outside of the actual repo since it would require setting up `heptapod-runner` locally, making a Git repo with the right changes, etc. It's not worth my time at this point. If this fails, I'll try to ask for help from Georges, the maintainer of Heptapod.

heptapod-ci: don't run pipelines for topic-less branches See inline comment for more details.