Change NoPBTextMeter to display no output at all

[dmach]

Fixes: #1428

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (53968bf) 30.40% compared to head (0d239cc) 30.40%.
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1433   +/-   ##
=======================================
  Coverage   30.40%   30.40%           
=======================================
  Files          49       49           
  Lines       17712    17708    -4     
=======================================
- Hits         5385     5384    -1     
+ Misses      12327    12324    -3     

Files	Coverage Δ
osc/meter.py	52.77% <0.00%> (+2.77%)	⬆️

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