[CK_BUILDER] Fix missing template arguments in ConvBwdWeightV3 test

Add DirectLoad and NumGroupsToMerge template parameters to the
DeviceGroupedConvBwdWeight_Xdl_CShuffleV3 test instantiation. These
parameters were added to the device implementation in #3648 but the
forward declaration in the reflect header does not have default values,
requiring explicit specification in test code.

experimental/builder/test/conv/ck/test_conv_traits.cpp

@@ -812,7 +812,9 @@ TEST_F(ConvTraitsTest, ConvBwdWeightXdlCshuffleV3TraitsExtraction)
         ck::BlockGemmPipelineScheduler::Intrawave, // BlkGemmPipeSched
         ck::BlockGemmPipelineVersion::v1,          // BlkGemmPipelineVer
         ck::half_t,                                // AComputeDataType
-        ck::half_t>;                               // BComputeDataType
+        ck::half_t,                                // BComputeDataType
+        false,                                     // DirectLoad
+        1>;                                        // NumGroupsToMerge
 
     // Use ConvTraitsTmpl to extract compile-time information
     const auto traits = ck_tile::reflect::conv::instance_to_conv_traits<DeviceInstance>();