tests: Set progress widget geometry.

This hopefully fixes this warning on Windows:

    QWindowsWindow::setGeometryDp: Unable to set geometry 113x16+192+124 on
    QWidgetWindow/'ProgressClassWindow'. Resulting geometry:  124x16+192+124
    (frame: 8, 31, 8, 8, custom margin: 0, 0, 0, 0, minimum size: 0x0, maximum
    size: 16777215x16777215).

tests/mainwindow/statusbar/test_progress.py

@@ -39,6 +39,7 @@ def progress_widget(qtbot, monkeypatch, config_stub):
         'qutebrowser.mainwindow.statusbar.progress.style.config', config_stub)
     widget = Progress()
     qtbot.add_widget(widget)
+    widget.setGeometry(200, 200, 200, 200)
     assert not widget.isVisible()
     assert not widget.isTextVisible()
     return widget