test: use leaf image prompt in video-ref r2v e2e

Switch the seed-image prompt from a cat sketch to a green leaf for a
simpler, more reliably-generated reference frame.

Author: XXPermanentXX

packages/cli/tests/e2e/video-ref-r2v.e2e.test.ts

@@ -69,7 +69,7 @@ describe.skipIf(!isBailianE2EVideoEnabled() || !isDashScopeE2EReady())(
         "--model",
         "qwen-image-2.0",
         "--prompt",
-        "一只简笔画小猫，白底",
+        "一片绿色的树叶，白底",
         "--out-dir",
         outDir,
         "--out-prefix",