Disable conpty by default

- Cursor flickering in powershell is _really_ annoying and there is no way
  to work around it reliably. It's happening because conpty hides and shows
  the cursor many times when it doesn't really need to, and since data isn't
  batched xterm.js renders as much as possible which shows the cursor in
  positions.
- Kill doesn't kill the process, this is likely a problem on our end.

Part of #66001

src/vs/workbench/parts/terminal/electron-browser/terminal.contribution.ts

@@ -392,9 +392,9 @@ configurationRegistry.registerConfiguration({
 			default: 'inherited'
 		},
 		'terminal.integrated.windowsEnableConpty': {
-			description: nls.localize('terminal.integrated.windowsEnableConpty', "Whether to use ConPTY for Windows terminal process communication (requires Windows 10 build number 17692+). The default is to enable this on Windows 10 build number 17692+. Winpty will be used if this is false."),
+			description: nls.localize('terminal.integrated.windowsEnableConpty', "Whether to use ConPTY for Windows terminal process communication (requires Windows 10 build number 17692+). Winpty will be used if this is false."),
 			type: 'boolean',
-			default: true
+			default: false
 		}
 	}
 });