Empty swipes are not handled by ensureSwipes. (#4828)

* Handle empty swipes.

* Add warning.

* Replace with forEach

* Replace with for loop

---------

Co-authored-by: user <user@exmaple.com>
Co-authored-by: Cohee <18619528+Cohee1207@users.noreply.github.com>

public/script.js

@@ -6404,6 +6404,14 @@ export function ensureSwipes(message) {
         updated = true;
     }
 
+    for (let i = 0; i < message.swipes.length; i++) {
+        if (typeof message.swipes[i] !== 'string') {
+            updated = true;
+            console.warn('The message had a swipe that is not a string. It has has been set to \'\'.', message);
+            message.swipes[i] = '';
+        }
+    }
+
     if (typeof message.swipe_id !== 'number') {
         message.swipe_id = 0;
         updated = true;