ui,popups: improved dialog resizing

If the first popup shown misaligned the dialog, the next dialogs were
not resized to the original size.

ui/opensnitch/dialogs/prompt.py

@@ -67,8 +67,8 @@ def __init__(self, parent=None, appicon=None):
         self.setWindowIcon(appicon)
         self.installEventFilter(self)
 
-        self._width = None
-        self._height = None
+        self._width = self.width()
+        self._height = self.height()
 
         dialog_geometry = self._cfg.getSettings("promptDialog/geometry")
         if dialog_geometry == QtCore.QByteArray: