test!: don't literally launch tutor and import demo course as part of CI

This takes a long time to run and feels like overkill, especially
since the Demo Course maintainers regularly import this course into
a real instace.

While importing with Tutor for every PR might catch an OLX issue once
in a while, I think it's more likely that something about Tutor will
change and CI will start failing.

A better approach would be to just run olxcleaner on every PR.

.github/workflows/ci.yml

@@ -9,31 +9,6 @@ on:
         branches: ["main"]
 
 jobs:
-    test_import:
-        runs-on: ubuntu-latest
-        steps:
-            - name: Check out this repo
-              uses: actions/checkout@v2
-
-            - name: Install latest Tutor
-              run: pip install tutor
-
-            - name: Disable tutor-mfe
-              run: |
-                  tutor plugins disable mfe
-                  tutor config save
-
-            - name: Launch Tutor
-              run: tutor local launch --non-interactive
-
-            # We need a user to exist, since all libraries need an owner.
-            # The Makefile assigns the library to the user named 'admin', so
-            # we name create an 'admin' user here.
-            - name: create admin user
-              run: tutor local do createuser admin [email protected] --password admin --staff --superuser
-
-            - name: import course & libraries
-              run: make import
 
     source_and_tars_match:
         runs-on: ubuntu-latest