Do not use ess.reduce's ScatteringRunType

This avoid stray types such as VanadiumRun appearing in workflows. This
"bug" happened because initially ScatteringRunType only included runs
relevant for SANS, which was a bad assumption. There was no harm from
this, except for unused nodes in graphs.

Author: SimonHeybrock

src/ess/sans/types.py

@@ -28,7 +28,6 @@
 NeXusMonitorName = reduce_t.NeXusName
 NeXusComponent = reduce_t.NeXusComponent
 SampleRun = reduce_t.SampleRun
-ScatteringRunType = reduce_t.ScatteringRunType
 Transmission = reduce_t.TransmissionMonitor
 TransmissionRun = reduce_t.TransmissionRun
 
@@ -44,6 +43,8 @@
     TransmissionRun[SampleRun],
     TransmissionRun[BackgroundRun],
 )
+ScatteringRunType = TypeVar('ScatteringRunType', BackgroundRun, SampleRun)
+
 
 UncertaintyBroadcastMode = _UncertaintyBroadcastMode