UI: Make projector display resolutions DPI-aware

Follow up to PR #3988 and commit
5cdd084c7f946e385748e96306223cd1f1d05b3e.
Without this change, displays listed as projector targets on systems
using a fractional scaling factor (e.g., 125%, 150%, 175%) will show an
incorrect width and height for their size. For a display with 125%
scaling, OBS would show 1536x864 instead of 1920x1080. With this change,
it will show 1920x1080.

UI/window-basic-main.cpp

@@ -4718,6 +4718,7 @@ void OBSBasic::AddProjectorMenuMonitors(QMenu *parent, QObject *target,
 	for (int i = 0; i < screens.size(); i++) {
 		QScreen *screen = screens[i];
 		QRect screenGeometry = screen->geometry();
+		qreal ratio = screen->devicePixelRatio();
 		QString name = "";
 #ifdef _WIN32
 		QTextStream fullname(&name);
@@ -4743,8 +4744,10 @@ void OBSBasic::AddProjectorMenuMonitors(QMenu *parent, QObject *target,
 		QString str =
 			QString("%1: %2x%3 @ %4,%5")
 				.arg(name,
-				     QString::number(screenGeometry.width()),
-				     QString::number(screenGeometry.height()),
+				     QString::number(screenGeometry.width() *
+						     ratio),
+				     QString::number(screenGeometry.height() *
+						     ratio),
 				     QString::number(screenGeometry.x()),
 				     QString::number(screenGeometry.y()));