When calling QAccessibleTextInterface::textAtOffset on a QLineEdit's accessible object using the text length for the offset parameter, this triggers an infinite recursion and the app freezes and has to be killed manually.

Issue was originally mentioned here (but is independent of that particular change): https://codereview.qt-project.org/c/qt/qtbase/+/679128/comments/858485c5_cd1a76ea

Sample steps to reproduce, using the corresponding methods of the AT-SPI2 Text interface on Linux:

1. Build and run this sample program

   #include <QApplication>
   #include <QLineEdit>
   #include <QMainWindow>
   #include <QTextEdit>
   #include <QVBoxLayout>
   
   int main(int argc, char* argv[])
   {
       QApplication a(argc, argv);
       QMainWindow w;
   
       QWidget* widget = new QWidget;
       w.setCentralWidget(widget);
   
       QVBoxLayout* layout = new QVBoxLayout(widget);
   
       layout->addWidget(new QLineEdit("Hello world"));
       layout->addWidget(new QTextEdit("Hello world"));
   
       w.show();
       return a.exec();
   }

2. start Accerciser Accessibility Explorer ( https://gitlab.gnome.org/GNOME/accerciser )
3. in Accerciser's treeview of the sample program's a11y hierarchy, select the object for the QLineEdit
4. in Accerciser's IPython console, try to get word at the end, using the AT-SPI2 Text interface

   In [117]: text = acc.queryText()
   In [118]: text.characterCount
   Out[118]: 11
   In [119]: text.getTextAtOffset(11, 1)
   ---------------------------------------------------------------------------
   Error                                     Traceback (most recent call last)
   Cell In[119], line 1
   ----> 1 text.getTextAtOffset(11, 1)
   
   File /usr/lib/python3/dist-packages/pyatspi/text.py:469, in Text.getTextAtOffset(self, offset, type)
       444 def getTextAtOffset(self, offset, type):
       445         """
       446         Deprecated in favor of getStringAtOffset.
       447         Obtain a subset of the text content of an object which includes
      (...)
       467         the object, delimited by the specified boundary condition.
       468         """
   --> 469         ret = Atspi.Text.get_text_at_offset(self.obj, offset, type)
       470         return textRangeToList(ret)
   
   Error: atspi_error: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken. (1)
   

Actual result:
The sample app freezes.
Accerciser prints an error because it didn't receive any result from the app.

Expected result:
The app should return a result and remain responsive.