[script set -e] enable feature flag (#1533)

## Summary

## How was it tested?

Author: savil

internal/boxcli/featureflag/script_exit_on_error.go

@@ -5,4 +5,4 @@ package featureflag
 
 // ScriptExitOnError controls whether scripts defined in devbox.json
 // and executed via `devbox run` should exit if any command within them errors.
-var ScriptExitOnError = disable("SCRIPT_EXIT_ON_ERROR")
+var ScriptExitOnError = enable("SCRIPT_EXIT_ON_ERROR")

internal/shellgen/scripts.go

@@ -103,9 +103,7 @@ func WriteScriptFile(devbox devboxer, name, body string) (err error) {
 	defer script.Close() // best effort: close file
 
 	if featureflag.ScriptExitOnError.Enabled() {
-		// NOTE: Devbox scripts will run using `sh` for consistency.
-		// However, we need to disable this for `fish` shell if/when we allow this for init_hooks,
-		// since init_hooks run in the host shell, and not `sh`.
+		// NOTE: Devbox scripts run using `sh` for consistency.
 		body = fmt.Sprintf("set -e\n\n%s", body)
 	}
 	_, err = script.WriteString(body)