Move TRT include_directories to outside scope (#14622)
Signed-off-by: Kevin Chen <kevinch@nvidia.com>
### Description
Previously `include_directories(${TENSORRT_INCLUDE_DIR})` was only done
if `onnxruntime_USE_TENSORRT_BUILTIN_PARSER` was false. This would cause
a build failure when the switch was true as the include directory was
not added.
### Motivation and Context
Fixes TRT build when `onnxruntime_USE_TENSORRT_BUILTIN_PARSER` is true.
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Signed-off-by: Kevin Chen <kevinch@nvidia.com>
