Running app in C:\Windows\System32 gives the error `rundll32 resolves to executable in current directory (.\rundll32.exe)`

Checklist

• I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
• This issue only relates to a single bug. I will open new issues for any other problems.

Describe the bug

Running app in C:\Windows\System32 gives the error rundll32 resolves to executable in current directory (.\rundll32.exe)

The code calls fyne.CurrentApp().OpenURL(url)

Which hits this code (windows):

func (a *fyneApp) OpenURL(url *url.URL) error {
	cmd := a.exec("rundll32", "url.dll,FileProtocolHandler", url.String())
	cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
	return cmd.Run()
}

But with the go 1.19 changes to PATH lookups this fails. The same error will happen for all other fyne calls to "rundll32". I assume the fix is to reference the full path to it: "C:\Windows\System32\rundll32"

See https://go.dev/doc/go1.19 - PATH lookups for details.

How to reproduce

1. Create fyne app with golang 1.19 on Windows that calls fyne.CurrentApp().OpenURL(url)
2. Run the app with the working directory as C:\Windows\System32
3. Notice the error.

Screenshots

No response

Example code

fyne.CurrentApp().OpenURL(url)

Fyne version

2.2.3

Go compiler version

1.19.1

Operating system

Windows

Operating system version

Windows 10

Additional Information

No response