Fixing track masking for the input variable plots
Summary
This MR introduces the following changes
- Adding
valid
as the default track mask variable. Ifvalid
is not available,ptfrac
will be used instead. - Adding new unit test R22 test file (with
tracks_loose
andvalid
flag present) (Will be added when this MR is approved, otherwise all other pipelines will fail.)
Relates to the following issues
- Closes #196 (closed)