It's redundant since the job explicitly installs the proper version in
the previous step, and also running that prematurely pulls a bunch of
JARs from Maven Central.

This should shave 20 seconds from the CI runs.

* Remove `project.clj` from Percy workflows

* Replace `project.clj` with `deps.edn` in `build-for-test` script

* Update reference to the `project.clj` in the comment