ci: remove bloat from merge group

[kilpatty]

Our cargo bloat action does not work on "merge_group" actions I believe, it also hasn't been updated since 2021 - let's look at some other options, or run one ourselves.

[kilpatty]

I believe that I was wrong in my previous diagnosis - bloat is failing not on "merge_group" runs, but rather on scheduled runs. I have implemeneted a quick fix for that, but I do believe there are other scenarios where this could fail.

Permanent solutions:

1. Move Bloat to it's own workflow file
2. Figure out an "if" statement that controls for whether we are comparing any branches. I believe there is one GITHUB_BASE_REF which will be empty if there is no base ref, so that is something e could try to implement with