[Typescript] Fix warning logs for additional properties that have not been set

[Mattias-Sehlstedt]

Utilizes the Codegen parsing introduced in #18935 to get rid of warnings for incorrectly set additionalProperties when they are not set rather than incorrectly set.

I.e., the client was getting The value (generator's option) must be either boolean or string. Default to "false". for useRxJS when generating a client, even though they had not even stated a value for it.

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[wing328]

thanks for the PR

can we still keep (generator's option) in the log some users misunderstood this option as a global option instead if I remember correctly?

[Mattias-Sehlstedt]

I have readded that information to the log