Add some roomserver UTs

[S7evinK]

Adds tests for QueryRestrictedJoinAllowed, IsServerAllowed and PerformRoomUpgrade. Refactors the QueryRoomVersionForRoom method to accept a string and return a gmsl.RoomVersion instead of req/resp structs.
Adds some more caching for GetStateEvent

This should also fix #2912 by ignoring state events belonging to other users.

[codecov]

Codecov Report

Patch coverage: 40.90% and project coverage change: +0.04 🎉

Comparison is base (ed19efc) 66.70% compared to head (3c96656) 66.75%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3067      +/-   ##
==========================================
+ Coverage   66.70%   66.75%   +0.04%     
==========================================
  Files         495      495              
  Lines       53559    53543      -16     
==========================================
+ Hits        35727    35741      +14     
+ Misses      14186    14168      -18     
+ Partials     3646     3634      -12     

Flag	Coverage Δ
unittests	47.96% <40.90%> (+0.90%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
clientapi/routing/profile.go	53.08% <0.00%> (-1.02%)	⬇️
clientapi/routing/sendevent.go	72.19% <0.00%> (-1.47%)	⬇️
clientapi/routing/server_notices.go	71.25% <ø> (-0.12%)	⬇️
federationapi/routing/join.go	52.21% <0.00%> (-2.33%)	⬇️
federationapi/routing/leave.go	42.85% <0.00%> (-1.46%)	⬇️
federationapi/routing/peek.go	0.00% <0.00%> (ø)
federationapi/routing/threepid.go	0.00% <0.00%> (ø)
roomserver/internal/input/input_events.go	60.79% <0.00%> (+1.97%)	⬆️
setup/mscs/msc2836/msc2836.go	42.85% <0.00%> (+0.14%)	⬆️
clientapi/routing/createroom.go	61.24% <25.00%> (-2.86%)	⬇️
... and 5 more

... and 16 files with indirect coverage changes

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[devonh]

LGTM!