[widgets][plotterparameterseditor] Use ValueError instead of Exception

logging.exception instead of logging.error
4 jobs for issue-278-plotterparam-default-value in 26 minutes and 29 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #204775
docker
build_linux_36

00:11:38

90.0%
passed #204776
docker
build_linux_37

00:11:21

90.0%
passed #204773
macosx
build_macosx_36

00:26:29

90.0%
passed #204774
macosx
build_macosx_37

00:25:40

90.0%