Improve StringMatchCandidate::new interface (#22011)

Release Notes:

- N/A

crates/extensions_ui/src/extensions_ui.rs

@@ -328,11 +328,7 @@ impl ExtensionsPage {
                 let match_candidates = dev_extensions
                     .iter()
                     .enumerate()
-                    .map(|(ix, manifest)| StringMatchCandidate {
-                        id: ix,
-                        string: manifest.name.clone(),
-                        char_bag: manifest.name.as_str().into(),
-                    })
+                    .map(|(ix, manifest)| StringMatchCandidate::new(ix, &manifest.name))
                     .collect::<Vec<_>>();
 
                 let matches = match_strings(