I found some flaws with the last version I submitted so here's a new one with the flaws fixed.
The previous script assumed that G90 and M82 were active. While this was the case with CuraLE 2.6, CuraLE 3.2 has a special setting for relative extrusion (M83). If relative extrusion is set then each instance of the plugin would set absolute extrusion with undesireable results.
The script has provisions for a retraction and an extrusion amount. This extrusion amount could be set high enough that the nozzle spits out a string of filament. To allow the operator to clean the nozzle, a new parameter, Pause Time, has been added which specifies a time (in seconds) to pause after this extrusion (which happens after the operator has pushed the button). This pause is a G4 so it does not need another operator button push (I assume the operator is sitting right there because they just pushed the button).
If you made any changes to my previous version, then they will need to be applied to this one.