Allow 'url join' to print username without password (#11697)

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# Description
Fixes: https://github.com/nushell/nushell/issues/11677
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# Tests + Formatting
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```
'https://example.com' | url parse | update scheme ssh | upda
te username user | url join
# => ssh://user@example.com/
'https://example.com' | url parse | update scheme ssh | upda
te password hackme | url join
# => ssh://example.com/
'https://example.com' | url parse | update scheme ssh | update username user | update password hackme | url join
# => ssh://user:hackme@example.com/
```
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---------

Co-authored-by: Richard Westhaver <ellis@rwest.io>

crates/nu-command/src/network/url/join.rs

@@ -317,13 +317,11 @@ impl UrlComponents {
     }
 
     pub fn to_url(&self, span: Span) -> Result<String, ShellError> {
-        let mut user_and_pwd: String = String::from("");
-
-        if let Some(usr) = &self.username {
-            if let Some(pwd) = &self.password {
-                user_and_pwd = format!("{usr}:{pwd}@");
-            }
-        }
+        let user_and_pwd = match (&self.username, &self.password) {
+            (Some(usr), Some(pwd)) => format!("{usr}:{pwd}@"),
+            (Some(usr), None) => format!("{usr}@"),
+            _ => String::from(""),
+        };
 
         let scheme_result = match &self.scheme {
             Some(s) => Ok(s),

crates/nu-command/tests/commands/url/join.rs

@@ -31,7 +31,7 @@ fn url_join_with_only_user() {
             "#
     ));
 
-    assert_eq!(actual.out, "http://localhost");
+    assert_eq!(actual.out, "http://usr@localhost");
 }
 
 #[test]