Add option for GraphViewerToProto serialization to skip writing data (#25263)
### Description
Adds `include_initializer_data` option to `GraphViewerToProto` to skip
writing initializer raw data and external data when serializing.
### Motivation and Context
For TensorRT EP, partitioned graphs must be serialized to proto in order
for getCapability() to run. For cases where the weights are not strictly
needed (i.e. weightless engines), serializing the graph without
initializer data reduces the overall memory required.
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Signed-off-by: Kevin Chen <kevinch@nvidia.com>