fix(icalendar): Support object rrule by converting to string

icalendar_test.ts

@@ -196,13 +196,13 @@ Deno.test("expandRecurrences - object rrule (Reproduction of missing events)", (
 
   try {
     const results = expandRecurrences(icsEvent, 30);
-    // Currently, it returns [icsEvent] (length 1) and logs a warning.
-    // This confirms that it is NOT expanding it.
-    assertEquals(results.length, 1);
+    // Should now return multiple occurrences
+    assert(results.length > 1, `Expected > 1 occurrences, got ${results.length}`);
+    assertEquals(results[0].recurrent, true);
   } finally {
     console.warn = originalConsoleWarn;
   }
   
-  assert(warningLogged, "Should have logged a warning for object rrule");
+  assert(!warningLogged, "Should NOT have logged a warning for object rrule");
 });