adopt the removal of stringify-with-ref library change

[ArcturusZhang]

Description

Adopts the changes from microsoft/typespec#7455
Supersedes #5339

it turns out we have quite a few issues around the convenientApi being true or false.

The test project FirstTest-TypeSpec has the global setting of generate-convenient-methods: false, therefore if operations do not have @convenientApi(true), they should not have convenient methods.
But in fact, quite a few such operations have convenience methods which leads to issues because TCGC would take that information correct and models/enums related will not be included.

I think we would not bother to fix that since it only happens in DPG - which will soon be superseded by the new generator.
To make everything works correctly, I just refines the typespec files so that our expectation for convenient methods would align with TCGC's

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