Always prompt to return from subprocess if there was an error (#3410)

- **PR Description**

When lazygit suspends itself to the background to run an external
command, and the command returns a non-zero exit code, always show the
prompt for pressing enter to return to lazygit, even if the
`promptToReturnFromSubprocess` is set to `false`. The rationale is that
if the process returned an error, it likely also printed some error
message to the console that users will always want to read.

I was considering turning the `promptToReturnFromSubprocess` config into
an enum with values `never`, `onlyOnError`, `always`, but then I felt
that `onlyOnError` is really the only sensible choice for people who
have it set to `false` now, so I just hard-coded that.

pkg/gui/gui.go

@@ -824,7 +824,7 @@ func (gui *Gui) runSubprocess(cmdObj oscommands.ICmdObj) error { //nolint:unpara
 	subprocess.Stderr = io.Discard
 	subprocess.Stdin = nil
 
-	if gui.Config.GetUserConfig().PromptToReturnFromSubprocess {
+	if gui.integrationTest == nil && (gui.Config.GetUserConfig().PromptToReturnFromSubprocess || err != nil) {
 		fmt.Fprintf(os.Stdout, "\n%s", style.FgGreen.Sprint(gui.Tr.PressEnterToReturn))
 
 		// scan to buffer to prevent run unintentional operations when TUI resumes.