Don't show dropped students on project group table

[mgmodell]

To do this, I need to make sure that I remove a student from any project groups when I remove them from a project.

[mgmodell]

This was user error.

[mgmodell]

We should identify (or write) the test (feature[s] and scenario[s]) that checks for this.
The tests are in the features folder.

[mgmodell]

I think the scenario was an invited (but not accepted) student was then dropped. They remained in their group.