Hide TBB warnings when compiling

[lilleyse]

This is related to the USD update in Kit 107 - #746

[ 61%] Building CXX object src/core/CMakeFiles/CesiumOmniverseCore.dir/src/FabricTexture.cpp.o
In file included from /github/workspace/extern/nvidia/_build/target-deps/usd/release/include/pxr/base/work/dispatcher.h:37,
                 from /github/workspace/extern/nvidia/_build/target-deps/usd/release/include/pxr/usd/sdf/layer.h:46,
                 from /github/workspace/extern/nvidia/_build/target-deps/usd/release/include/pxr/usd/usd/schemaRegistry.h:31,
                 from /github/workspace/extern/nvidia/_build/target-deps/usd/release/include/pxr/usd/usd/primDefinition.h:29,
                 from /github/workspace/extern/nvidia/_build/target-deps/usd/release/include/pxr/usd/usd/primData.h:33,
                 from /github/workspace/extern/nvidia/_build/target-deps/usd/release/include/pxr/usd/usd/object.h:32,
                 from /github/workspace/extern/nvidia/_build/target-deps/usd/release/include/pxr/usd/usd/prim.h:32,
                 from /github/workspace/extern/nvidia/_build/target-deps/usd/release/include/pxr/usd/usd/schemaBase.h:29,
                 from /github/workspace/extern/nvidia/_build/target-deps/usd/release/include/pxr/usd/usd/typed.h:31,
                 from /github/workspace/src/plugins/CesiumUsdSchemas/src/CesiumUsdSchemas/rasterOverlay.h:8,
                 from /github/workspace/src/core/include/cesium/omniverse/UsdUtil.h:3,
                 from /github/workspace/src/core/src/FabricTexture.cpp:7:
/github/workspace/extern/nvidia/_build/target-deps/usd/release/include/tbb/task.h:21:139: note: ‘#pragma message: TBB Warning: tbb/task.h is deprecated. For details, please see Deprecated Features appendix in the TBB reference manual.’
   21 | #pragma message("TBB Warning: tbb/task.h is deprecated. For details, please see Deprecated Features appendix in the TBB reference manual.")
      |                                                                                                                                           ^

Adding #define TBB_SUPPRESS_DEPRECATED_MESSAGES 1 to the top of the generated schema files seems to fix it. Unfortunately not a permanent solution since the files will get overwritten when regenerated.

For some reason I didn't have any luck adding this define as part of the CMake build.