Fix missing update of BPM display

The problem was a missing redraw after changing the label. This led to a
stucked display, when the tempo dial is used. Now a redraw is added after
the label is changed.
5 jobs for 56-bug-in-tempo-dial in 47 seconds
Status Job ID Name Coverage
  Build
passed #2245
docker
build-publish

00:00:15

passed #2244
docker
build-test

00:00:23

 
  Test
failed #2246
docker allowed to fail
static-analysis

00:00:10

passed #2247
docker
test

00:00:11

71.0%
 
  Package
passed #2248
docker
package-AppImage

00:00:13

 
Name Stage Failure
failed
static-analysis Test
      46     12    427      2      74 Looper::process@110-183@src/looper.cxx
62 21 400 2 93 GridLogic::pressed@129-221@src/gridlogic.cxx
69 14 523 2 97 gui_header_callback@97-193@src/gui.cxx
328 79 2878 1 342 Gui::keyboardHandler@565-906@src/gui.cxx
==========================================================================================
Total nloc Avg.NLOC AvgCCN Avg.token Fun Cnt Warning cnt Fun Rt nloc Rt
------------------------------------------------------------------------------------------
19616 14.6 3.0 103.4 610 32 0.05 0.36
ERROR: Job failed: exit code 1