Back out changelist 7822943
Add deprecation path for ILiveLinkSource::IsSourceStillValid. Add a new function IsSourceValid
#rb none
#jira UE-78470
#ROBOMERGE-SOURCE: CL 7839258 in //UE4/Release-4.23/...
#ROBOMERGE-BOT: RELEASE (Release-4.23 -> Main) (v389-7813075)
[CL 7839261 by patrick boutot in Main branch]
#jira UE-76056
#rb simon.therriault
#ROBOMERGE-SOURCE: CL 7790661 in //UE4/Release-4.23/...
#ROBOMERGE-BOT: RELEASE (Release-4.23 -> Main) (v388-7785529)
[CL 7793081 by patrick boutot in Main branch]
-Hand merging from Dev-vr
-Was crashing due to continued use of a structure which had been MoveTemp-ed to another.
-Now we copy that data before MoveTemp.
-Rearranged the function a bit to get everything into blocks of similar update frequency.
#review-7094325
#rb jason.bestimt patrick.boutot
[CL 7097463 by Jeff Fisher in Main branch]
#jira UE-76419
#rb simon.therriault, jason.bestimt
#ROBOMERGE-SOURCE: CL 7089737 in //UE4/Release-4.23/...
#ROBOMERGE-BOT: RELEASE (Release-4.23 -> Main) (v367-6836689)
[CL 7089744 by patrick boutot in Main branch]