cli: extract Ui::new() that creates ui with default config

Since ui object is needed to report read_config() error, it makes sense to
create ui first without fallible user configuration. Ui::for_terminal() will
be replaced with this function and ui.reset(read_config()?).

Default::default() is also added to silence clippy. If we prefer, Ui::new()
can be replaced with Ui::default().

src/cli_util.rs

@@ -1475,7 +1475,7 @@ pub fn create_ui() -> (Ui, Result<(), CommandError>) {
     match read_config() {
         Ok(user_settings) => (Ui::for_terminal(user_settings), Ok(())),
         Err(err) => {
-            let ui = Ui::for_terminal(UserSettings::from_config(crate::config::default_config()));
+            let ui = Ui::new();
             (ui, Err(CommandError::ConfigError(err.to_string())))
         }
     }

src/ui.rs

@@ -114,7 +114,17 @@ fn pager_setting(settings: &UserSettings) -> FullCommandArgs {
         .unwrap_or_else(|_| "less -FRX".into())
 }
 
+impl Default for Ui {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Ui {
+    pub fn new() -> Ui {
+        Self::for_terminal(UserSettings::from_config(crate::config::default_config()))
+    }
+
     pub fn for_terminal(settings: UserSettings) -> Ui {
         let cwd = std::env::current_dir().unwrap();
         let color = use_color(color_setting(&settings));