Change assignable coach landing page after login

[alexMet]

Summary

Change the assignable coach landing page after logging in from learn to coach.

References

#7611

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[jonboiser]

Looks good!

[jonboiser]

Looks good. I just noticed there are no tests for coach redirection here

kolibri/kolibri/core/test/test_key_urls.py

Line 52 in 42012df

def test_redirect_root_to_learn_if_logged_in(self):

So I'll add in new test cases for the Facility coach and Assignable coach