In phy-test and do-ra modes, we will trigger a UE context creation after
F1 Setup (because the DU is ready), in a later commit. However, before
this commit, E1 is started after the gnb_app (which triggers F1 Setup).
E1 starts an (integrated) CU-UP; if the E1 Setup arrives after the F1
setup (which creates a UE context), then the E1 setup handler will drop
the newly created RRC context for a do-ra/phy-test mode.
Avoid/minimize this by starting E1 first, so that E1 setup is done
before F1 Setup is completed (this does not make sure the problem does
not happen, but lowers the risk of the above problem).