remove app.config dpi stuff

mono does not like this (fixes #4002)

src/BizHawk.Client.EmuHawk/DisplayManager/DisplayManager.cs

@@ -52,10 +52,11 @@ namespace BizHawk.Client.EmuHawk
 		public override Size GetPanelNativeSize() => _presentationPanel.NativeSize;
 
 		protected override int GetGraphicsControlDpi()
-			=> OSTailoredCode.IsUnixHost ? DisplayManagerBase.DEFAULT_DPI : GraphicsControlDpi;
-
-		// DeviceDpi is not available under mono, so we need to have this access wrapped in a separate function
-		private int GraphicsControlDpi => _graphicsControl.DeviceDpi;
+		{
+			return OSTailoredCode.IsUnixHost
+				? DEFAULT_DPI
+				: Win32Imports.GetDpiForWindow(_graphicsControl.Handle);
+		}
 
 		protected override Point GraphicsControlPointToClient(Point p) => _graphicsControl.PointToClient(p);
 

src/BizHawk.Client.EmuHawk/app.config

@@ -7,7 +7,4 @@
 		<loadFromRemoteSources enabled="true"/>
 		<gcAllowVeryLargeObjects enabled="true"/>
 	</runtime>
-	<System.Windows.Forms.ApplicationConfigurationSection>
-		<add key="DpiAwareness" value="PerMonitorV2" />
-	</System.Windows.Forms.ApplicationConfigurationSection>
 </configuration>

src/BizHawk.Common/Win32/Win32Imports.cs

@@ -67,5 +67,8 @@ namespace BizHawk.Common
 
 		[DllImport("user32.dll", ExactSpelling = true)]
 		public static extern int TrackPopupMenuEx(IntPtr hmenu, TPM fuFlags, int x, int y, IntPtr hwnd, IntPtr lptpm);
+
+		[DllImport("user32.dll", ExactSpelling = true)]
+		public static extern int GetDpiForWindow(IntPtr hwnd);
 	}
 }