Check NodeArg has name in ORT formal model load (#27297)
### Description
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Check for invalid node arg when loading ORT format model. A node arg
would always have a valid string in an ORT created model so this
requires manual editing of the model to make it invalid.
### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
