Adopt examples from TCGC

[ArcturusZhang]

Fixes #4980
Fixes #5006

Description

To adopt the example information from TCGC, we are taking the following steps, and this PR is the second step (first step is done in the typespec repo PR).

1. Update the emitter so that the emitter could spit out the examples from TCGC.
2. Refine our code in DPG so that the sample generator made for DPG is able to write out those examples, as if they are the mock examples.
3. Refine our code in MPG so that the examples for mgmt could be written when the input is typespec.
4. Possible follow ups: use the responses, now the responses in examples are not used.

Checklist

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