Check import behavior for QtCharts module

[dalthviz]

... the import here (for the QtCharts module) should give QtCharts (as done for the PyQt5 case) or everything under QtCharts (as done for PySide2) @ccordoba12 ?

I mean:

• PyQt5: ... .QtChart import *
• PyQt6, PySide2, PySide6: ... .QtCharts import *

or

• PyQt5: ... import QtChart as QtCharts
• PyQt6, PySide2, PySide6: ... import QtCharts

Edit: Checking, I think for PySide2 the actual import should be QtCharts.QtCharts and update the test being done currently (since it does something like qtpy.QtCharts.QtCharts) if the idea is to import all inside QtCharts instead of only QtCharts

Originally posted by @dalthviz in #255 (comment)

[ccordoba12]

Ok, this is a thorny issue but I think we should expose this module like it's done for PyQt6 and PySide6, i.e. like this:

• PyQt5: from PyQt5.QtChart import *
• PyQt6: from PyQt6.QtCharts import *
• PySide2: from PySide2.QtCharts.QtCharts import *
• PySide6: from PySide6.QtCharts import *

Another important thing to add is an error message similar to one for PyQt5 but for PyQt6 because that module needs to be installed separately.