fix: Multiplexed stream is not present in OriginMapStore Redis db

[chakphanu]

#1577

change syntax from

GetLinkedInputStream() != nullptr && GetLinkedInputStream()->IsFromOriginMapStore() == false

GetLinkedInputStream()	GetLinkedInputStream()->IsFromOriginMapStore()	GetLinkedInputStream() != nullptr && GetLinkedInputStream()->IsFromOriginMapStore() == false
nullptr	N/A	false
not nullptr	false	true
not nullptr	true	false

to

!(GetLinkedInputStream() != nullptr && GetLinkedInputStream()->IsFromOriginMapStore())

GetLinkedInputStream()	GetLinkedInputStream()->IsFromOriginMapStore()	GetLinkedInputStream() != nullptr && GetLinkedInputStream()->IsFromOriginMapStore()	!(GetLinkedInputStream() != nullptr && GetLinkedInputStream()->IsFromOriginMapStore())
nullptr	N/A	false	true
not nullptr	false	false	true
not nullptr	true	true	false

And for readble, create new private method OvtStream::IsFromOriginMapStore for reusing in OvtStream::Start() and OvtStream::Stop()

[getroot]

I reviewed the code again, its purpose is to prevent registering the stream generated from OriginMapStore again. Since the stream generated from OVT is an Input Stream itself (Relay mode), just checking IsFromOriginMapStore() was enough. Thanks for the PR.