Have better testing for transfer-rendered.yml

[cansavvy]

transfer-rendered.yml has been ran in quite a bit on this repo pair because we almost never merge changes to the Rmds here.

See this mini saga: fhdsl/FH_Cluster_101#40

But we should figure out a way to make sure that this GHA is still working even when we aren't pushing changes to the Rmds. Might be a tad tricky to make sure it does that here but doesn't continue to over-transfer once this has been converted to a template.

[cansavvy]

Related to this we need to have render_leanpub: yes in this template repo but have render_leanpub: no once it has been turned into a template. Something to add to the set up GHA