[Bug] grass GUI fails to start with wxPython 4.1.0

[ggardet]

Describe the bug
grass GUI fails to start with wxPython 4.1.0. It returns:

Traceback (most recent call last):
  File "/usr/lib64/grass78/gui/wxpython/gis_set.py", line 1148, in OnInit
    StartUp = GRASSStartup()
  File "/usr/lib64/grass78/gui/wxpython/gis_set.py", line 224, in __init__
    self._do_layout()
  File "/usr/lib64/grass78/gui/wxpython/gis_set.py", line 392, in _do_layout
    location_boxsizer = layout_list_box(
  File "/usr/lib64/grass78/gui/wxpython/gis_set.py", line 374, in layout_list_box
    main_sizer.Add(buttons_sizer, proportion=0,
wx._core.wxAssertionError: C++ assertion "!(flags & wxALIGN_CENTRE_HORIZONTAL)" failed at /home/abuild/rpmbuild/BUILD/wxPython-4.1.0/ext/wxWidgets/src/common/sizer.cpp(2102) in DoInsert(): Horizontal alignment flags are ignored in horizontal sizers
OnInit returned false, exiting...

To Reproduce
Try to start grass --gui with wxPython 4.1.0.

Expected behavior
GUI should show up.

Screenshots
N/A

System description (please complete the following information):

• Operating System: openSUSE Tumbleweed
• GRASS GIS version: 7.8.1

Additional context
There are very likely additional places to fix.
In https://wxpython.org/news/2020-04-24-wxpython-410-release/index.html they state:
Many of the deprecated items in wxWidgets and wxPython are being or have been removed. Be sure to test your code in a recent 4.0.x release with warnings enabled so you can see which class, method or function calls you need to change.

This is probably related to:

• wxWidgets/wxWidgets@78b98bf
• wxWidgets/wxWidgets@999d78a

[petrasovaa]

Thanks for letting us know and the PR, I will try to address this, there will be probably changes needed all over the GUI.

[petrasovaa]

As far as I could test, wxGUI should be working now with the new wx version (#570), needs to be merged to 7.8.4 after some testing in master.