`pkgdown` on PRs appears to be deploying to `dev`

[brookslogan]

E.g., see this vignette which includes changes from this unmerged PR. (I thought we were using a setting to disable this deployment if it's a PR; maybe that logic isn't right or a breaking change has occurred.)

[brookslogan]

Marking medium priority as this might lead to confusing docs; these might be limited to the dev site but we're also not merging to main very frequently yet.

[brookslogan]

Actually, these two both are the "old" version (with "nonseasonal" model) rather than the "new" version (with "reseasonal" name). Apparently I failed to build the PR branch docs with the new epiprocess; perhaps I needed to load_all() before build_site()? [This doesn't make sense; the text above is in the vignette source, not the package.] Anyway, doesn't appear to be a CI failure.

[Real issue was not realizing git checkout failed. Thought it wouldn't be possible without untracked local files, but forgot the PR branch was already checked out in a git worktree.]