change display_error.exit_code to false (#13873)

The idea comes from @amtoine, I think it would be good to keey
`display_error.exit_code` same value, if user is using default config or
using no config file at all.

crates/nu-protocol/src/config/display_errors.rs

@@ -22,7 +22,7 @@ impl DisplayErrors {
 impl Default for DisplayErrors {
     fn default() -> Self {
         Self {
-            exit_code: true,
+            exit_code: false,
             termination_signal: true,
         }
     }