wxGUI: fix calling coordselect validator

[petrasovaa]

Fixes using coordinate selection in dialogs:

Traceback (most recent call last):
  File "/home/anna/dev/grass/grass/dist.x86_64-pc-linux-
gnu/gui/wxpython/gui_core/gselect.py", line 2403, in
<lambda>

self.coordsField.Bind(wx.EVT_TEXT, lambda event:
self._draw(delay=1))
  File "/home/anna/dev/grass/grass/dist.x86_64-pc-linux-
gnu/gui/wxpython/gui_core/gselect.py", line 2451, in _draw

coords = self._getCoords()
  File "/home/anna/dev/grass/grass/dist.x86_64-pc-linux-
gnu/gui/wxpython/gui_core/gselect.py", line 2466, in
_getCoords

if self.coordsField.GetValidator().Validate():
TypeError
:
Validate() missing 1 required positional argument: 'parent'