Deno Deploy EA: settings change does not trigger rebuild

After getting the error `Specifier not found in cache [...] --cached-only is specified.`, I added `deno install` as the "Install command" in `app.deno.com/my-org/my-repo/settings`. This did not trigger a rebuild, which took me a while to understand.

Start by reproducing the behavior in app.deno.com/my-org/my-repo/settings: add `deno install` as the Install command after the cached-only error and check whether a rebuild starts. The payload names no repository files or tests, so done would require a confirmed rebuild after this settings change and a documented implementation location.

Written by the indexing model from the issue text.