fix: Llama3_1ChatWrapper types

[vlamanna]

Description of change

Fix the type mismatch in the Llama3_1ChatWrapper constructor.

Fixes #349

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[giladgd]

Thanks for the PR!

The _specialTokensTextForPreamble parameter is internal and should not be exposed.
I fixed this issue by hiding the _specialTokensTextForPreamble option from the function signature in the transpiled types in #351.
I'll release it in the next few days.