[Bugfix] Fix Hermes tool call parser with streaming

[johngerving]

Fixes an issue where the first argument returned from a function call is not parsed properly by hermes_tool_parser.py when the type of the argument is not a string. This caused the delta of an integer argument to be cut off in the final delta returned to the client, eventually causing the entire first argument of the tool call to be missing.

FIX #18108

[github-actions]

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[aarnphm]

Can you write a test case for this? Thanks

[longregen]

I stumbled into this as well.

Can you write a test case for this? Thanks

I'd be happy to collaborate with this. Are there examples of other similar tests that I can use as a guide?