Fix multifrequency plotting

9 jobs for mf_plotting in 8 minutes and 5 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build Docker
passed #898998
build_docker_from_cache

00:00:17

 
  Test
passed #899000
test_mpi

00:04:10

passed #898999
test_serial

00:04:48

81.0%
 
  Demo Runs
passed #899005
run_bernoulli

00:00:28

passed #899006
run_curve_fitting

00:00:26

passed #899002
run_getting_started_1

00:00:31

passed #899003
run_getting_started_2

00:01:09

passed #899004
run_getting_started_3

00:02:59

passed #899001
run_ipynb

00:01:22