Plot examples not working with pyside6

[nstelter-slac]

Describe the bug

For example, in examples/scatterplot/scatterplot.ui screen,

• zooming in/out (with mouse-wheel or click+drag) doesn't work
• example data-points are not rendered
• should work the same as on pyqt5

Same issue are seen in other plot examples (like waveform_plot.ui)
But tests for plot widgets look to still be passing.

Steps to reproduce

1. create conda env with python 3.13 and pyside6:

  $ conda create -n pydm-environment-pyside python pip numpy scipy six psutil pyqtgraph pydm -c conda-forge
  $ source activate pydm-environment
  $ pip install PySide6 # or can install with conda in earlier cmd

2. activate conda pyside6 env and export QT_API=pyside6

3. run the plot examples with pydm examples/... and try using scroll-wheel and click-dragging.
   (note: to run pydm-testing-ioc, can just use different conda env with python < 3.13.5 for now)

Expected behavior

Plot example functionality on pyside6 (interacting with mouse and displaying data) matches with pyqt5

Operating System.

Linux

OS Version Details.

No response

Python Version

3.13.5

Packages Version

Additional context.

No response

[jbellister-slac]

This specific issue is caused by https://bugreports.qt.io/browse/PYSIDE-3115

There is a separate issue where the plot still crashes even with downgrading, but the new pyside release is slated for August at the moment, so I'd like to wait on that before looking further