add missing thread lock to prevent race condition
add missing thread lock to prevent race condition

This fixes a bug added by #14469 where I moved a function call outside
of an existing lock but still in a threaded region.  This PR fixes that
nonsense.

harterj/moose,lindsayad/moose,laagesen/moose,laagesen/moose,idaholab/moose,laagesen/moose,lindsayad/moose,dschwen/moose,bwspenc/moose,milljm/moose,sapitts/moose,andrsd/moose,SudiptaBiswas/moose,harterj/moose,andrsd/moose,idaholab/moose,dschwen/moose,sapitts/moose,laagesen/moose,sapitts/moose,harterj/moose,bwspenc/moose,lindsayad/moose,milljm/moose,bwspenc/moose,SudiptaBiswas/moose,lindsayad/moose,jessecarterMOOSE/moose,idaholab/moose,dschwen/moose,dschwen/moose,bwspenc/moose,jessecarterMOOSE/moose,SudiptaBiswas/moose,bwspenc/moose,sapitts/moose,nuclear-wizard/moose,sapitts/moose,milljm/moose,nuclear-wizard/moose,SudiptaBiswas/moose,idaholab/moose,harterj/moose,nuclear-wizard/moose,lindsayad/moose,laagesen/moose,dschwen/moose,idaholab/moose,andrsd/moose,jessecarterMOOSE/moose,jessecarterMOOSE/moose,jessecarterMOOSE/moose,harterj/moose,andrsd/moose,milljm/moose,andrsd/moose,nuclear-wizard/moose,SudiptaBiswas/moose,milljm/moose