Allow preferred Alert button regardless of the style (#34253)

Summary:
See #32538 for the discussion

cc robbie-c

## Changelog

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[iOS] [Fixed] - Allow preferred Alert button regardless of the style

Pull Request resolved: #34253

Test Plan: Same test plan as PR mentioned above

Reviewed By: lunaleaps

Differential Revision: D38112619

Pulled By: cipolleschi

fbshipit-source-id: 2ac4fc6226a859e69f0df27913898effa5e092eb

Libraries/Alert/Alert.js

@@ -137,7 +137,8 @@ class Alert {
             cancelButtonKey = String(index);
           } else if (btn.style === 'destructive') {
             destructiveButtonKey = String(index);
-          } else if (btn.isPreferred) {
+          }
+          if (btn.isPreferred) {
             preferredButtonKey = String(index);
           }
           if (btn.text || index < (callbackOrButtons || []).length - 1) {