Change Windows Powershell default scheme to Campbell (#5432)

The "Campbell Powershell" color scheme does not have a high enough color contrast
ratio. Campbell does, so we're changing it there.

Closes (only upon validation) #5393.

src/cascadia/TerminalApp/defaults.json

@@ -31,7 +31,7 @@
             "name": "Windows PowerShell",
             "commandline": "powershell.exe",
             "icon": "ms-appx:///ProfileIcons/{61c54bbd-c2c6-5271-96e7-009a87ff44bf}.png",
-            "colorScheme": "Campbell Powershell",
+            "colorScheme": "Campbell",
             "antialiasingMode": "grayscale",
             "closeOnExit": "graceful",
             "cursorShape": "bar",