Regenerate Job Router with stream-style serialization and remove many Internal models

[alzimmermsft]

Description

Regenerates azure-communication-jobrouter with stream-style serialization enabled. Additionally, adds numerous code customizations so that the *Internal model mapping pattern can be reduced greatly, lowering maintenance costs and possible bugs when mapping handwritten models to generated models.

There will need to be a corresponding change in azure-rest-api-specs based on what I changed manually in models.tsp and tspconfig.yml while creating this PR. I will open that PR once this has approval.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

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• Title of the pull request is clear and informative.
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• Pull request includes test coverage for the included changes.

[azure-sdk]

API change check

APIView has identified API level changes in this PR and created following API reviews.

com.azure:azure-communication-jobrouter

[alzimmermsft]

@williamzhao87 could you take a look at this PR. It's onboarding Job Router to azure-json and using code customizations to remove a lot of the mapping logic from custom to generated types but having the generated types handle the same as the custom types.

[williamzhao87]

@alzimmermsft Thanks for submitting the PR with these extensive changes! Everything here looks good to me.

[williamzhao87]

Just curious, it's only the empty internal classes that cannot be removed, right?

[alzimmermsft]

I really never figured out what to do with this class and the similar Internal classes as they're defined in the TypeSpec without any properties but are used in service methods that are hidden from the public API, so I left them. These can be followed up on if they should be removed.