[Impeller] fixed CanRenderClippedRuntimeEffects for vulkan (#49912)

fixes flutter/flutter#141891

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: gaaclarke

impeller/aiks/aiks_unittests.cc

@@ -2742,7 +2742,8 @@ TEST_P(AiksTest, CanRenderClippedRuntimeEffects) {
 
 TEST_P(AiksTest, DrawPaintTransformsBounds) {
   auto runtime_stages = OpenAssetAsRuntimeStage("gradient.frag.iplr");
-  auto runtime_stage = runtime_stages[RuntimeStageBackend::kMetal];
+  auto runtime_stage =
+      runtime_stages[PlaygroundBackendToRuntimeStageBackend(GetBackend())];
   ASSERT_TRUE(runtime_stage);
   ASSERT_TRUE(runtime_stage->IsDirty());
 

impeller/golden_tests/golden_playground_test_mac.cc

@@ -58,9 +58,6 @@ static const std::vector<std::string> kSkipTests = {
     "impeller_Play_AiksTest_CanRenderClippedRuntimeEffects_Vulkan",
     "impeller_Play_AiksTest_CaptureContext_Metal",
     "impeller_Play_AiksTest_CaptureContext_Vulkan",
-    // TODO(https://github.com/flutter/flutter/issues/141891): This tests
-    // crashes on vulkan and needs to be fixed.
-    "impeller_Play_AiksTest_DrawPaintTransformsBounds_Vulkan",
 };
 
 namespace {