fix auth for inst groups not in our infos

[dsschult]

Bug with groups that don't have the mou attribute at all. I think this fixes it?

File "/home/app/.local/lib/python3.10/site-packages/dash/_callback.py", line 442, in add_context
output_value = func(*func_args, **func_kwargs) # %% callback invoked %%
File "/home/app/web_app/contents/institution_callbacks.py", line 287, in select_institution_value
_select_institution_value_dc(
File "/home/app/web_app/contents/institution_callbacks.py", line 299, in _select_institution_value_dc
f"'{du.triggered()}' -> select_institution_value() ({state.s_urlpath=} {state.s_snap_ts=} {CurrentUser.get_summary()=})"
File "/home/app/web_app/data_source/connections.py", line 145, in get_summary
"is_authenticated": CurrentUser.is_loggedin_with_permissions(),
File "/home/app/web_app/data_source/connections.py", line 169, in is_loggedin_with_permissions
if CurrentUser.get_institutions():
File "/home/app/web_app/data_source/connections.py", line 212, in get_institutions
if not infos[short_name].has_mou:
KeyError: 'WashU-StLouis'