[Bug]: autorest emitter problem of multipart + @bodyRoot + spread

[tadelesh]

Describe the bug

For parameter with spread model with @bodyRoot on a model property with multipart property and other query property, the autorest emitter behavior is weird. It will generate the header parameter twice and also will put the header parameter in the body model.

Reproduction

See playground.

Checklist

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