### Link to issue number:

Fixes nvaccess#17442

 ### Summary of the issue:

UIA has a `UIA_LabeledByPropertyId` property, see https://learn.microsoft.com/en-us/windows/win32/winauto/uiauto-automation-element-propids :

> Identifies the LabeledBy property, which is an automation element that contains the text label for this element.
> This property can be used to retrieve, for example, the static text label for a combo box.
> Variant type: VT_UNKNOWN
> Default value: NULL

However, that one was so far not taken into account by NVDA's "labeledBy" property for UIA elements.

 ### Description of user facing changes

In NVDA's Python console, retrieving the "labeledBy" property now works for UIA elements supporting the corresponding LabeledBy UIA property.

 ### Description of development approach

Override `NVDAObject._get_labeledBy` in UIA to retrieve and return the UIAElement reported by the `UIA_LabeledByPropertyId` property.

 ### Testing strategy:

1. start NVDA
2. build Qt's qtbase module including an additional change that implements support for `UIA_LabeledByPropertyId` in Qt ( https://codereview.qt-project.org/c/qt/qtbase/+/606710 )
3. run Qt's "calendarwidgets" sample app (`qtbase/examples/widgets/widgets/calendarwidget/calendarwidget.exe`)
4. move focus to the "Locale" combobox
5. open NVDA's Python console (Ctrl+Insert+Z)
6. print the object that the currently focused edit is labelled by and
   some of its properties:

    >>> focus.labeledBy
    <NVDAObjects.UIA.UIA object at 0x0BE47ED0>
    >>> focus.labeledBy.name
    'Locale'
    >>> focus.labeledBy.role
    <Role.STATICTEXT: 7>

 ### Known issues with pull request:

None

 ### Code Review Checklist:

- [x] Documentation:
  - Change log entry
  - User Documentation
  - Developer / Technical Documentation
  - Context sensitive help for GUI changes
- [x] Testing:
  - Unit tests
  - System (end to end) tests
  - Manual testing
- [x] UX of all users considered:
  - Speech
  - Braille
  - Low Vision
  - Different web browsers
  - Localization in other languages / culture than English
- [x] API is compatible with existing add-ons.
- [x] Security precautions taken.

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@coderabbitai summary

Requires `from __future__ import annotations` for Python < 3.14
to use `UIA` return type in the UIA class itself,
see https://peps.python.org/pep-0563/
and https://peps.python.org/pep-0649/