[CI] fixes buildkite (#6544)

tests/BUILD.bazel

@@ -15,13 +15,13 @@ cc_test(
         "namespace_test/namespace_test2_generated.h",
         "native_type_test_impl.cpp",
         "native_type_test_impl.h",
+        "optional_scalars_generated.h",
         "test.cpp",
         "test_assert.cpp",
         "test_assert.h",
         "test_builder.cpp",
         "test_builder.h",
         "union_vector/union_vector_generated.h",
-        "optional_scalars_generated.h",
     ],
     copts = [
         "-DFLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE",
@@ -44,6 +44,7 @@ cc_test(
         ":monsterdata_test.golden",
         ":monsterdata_test.json",
         ":native_type_test.fbs",
+        ":optional_scalars.fbs",
         ":prototest/imported.proto",
         ":prototest/test.golden",
         ":prototest/test.proto",
@@ -55,7 +56,6 @@ cc_test(
         ":unicode_test.json",
         ":union_vector/union_vector.fbs",
         ":union_vector/union_vector.json",
-        ":optional_scalars.fbs",
     ],
     includes = [
         "",