[Feature] Add combine-swagger feature to tcp-client

[allenjzhang]

Clear and concise description of the problem

During Brownfield conversion, it is important to have a combined swagger in order to do side by side comparison of conversion results.

Checklist

• [X] Follow our Code of Conduct
• [X] Check that this issue is about the Azure libraries for typespec. For feature request in the typespec language or core libraries file it in the TypeSpec repo
• [X] Read the docs.
• [X] Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[markcowl]

Can we verify that this is not already supported with the existing tool?