UI: Set a maximum height to properties scroll area

When a source has a lot of properties, the scroll area containing them
would try to expand to fit them all, often leaving the preview area
super squished.  So this just sets a maximum height for the properties
scroll area.

obs/window-basic-properties.cpp

@@ -61,6 +61,7 @@ OBSBasicProperties::OBSBasicProperties(QWidget *parent, OBSSource source_)
 
 	layout()->addWidget(view);
 	layout()->setAlignment(view, Qt::AlignBottom);
+	view->setMaximumHeight(250);
 	view->setMinimumHeight(150);
 	view->show();