Add typespec-rust emitter options for test-proxy

[heaths]

No description provided.

[heaths]

This is ready to merge. It *almost( works for me. Getting an error during compilation, but that's an issue with @azure-tools/typespec-rust:

Emitter "@azure-tools/typespec-rust" crashed! This is a bug.
Please file an issue at https://github.com/Azure/typespec-rust/issues

Error: model property kind header NYI
    at Adapter.getModel (file:///home/heaths/src/azure-sdk-for-rust/sdk/core/azure_core_test/TempTypeSpecFiles/node_modules/@azure-tools/typespec-rust/src/tcgcadapter/adapter.ts:194:17)
    at Adapter.adaptTypes (file:///home/heaths/src/azure-sdk-for-rust/sdk/core/azure_core_test/TempTypeSpecFiles/node_modules/@azure-tools/typespec-rust/src/tcgcadapter/adapter.ts:107:30)
    at Adapter.tcgcToCrate (file:///home/heaths/src/azure-sdk-for-rust/sdk/core/azure_core_test/TempTypeSpecFiles/node_modules/@azure-tools/typespec-rust/src/tcgcadapter/adapter.ts:59:10)
    at Object.$onEmit [as emitFunction] (file:///home/heaths/src/azure-sdk-for-rust/sdk/core/azure_core_test/TempTypeSpecFiles/node_modules/@azure-tools/typespec-rust/src/emitter.ts:22:25)
    at runEmitter (file:///home/heaths/src/azure-sdk-for-rust/sdk/core/azure_core_test/TempTypeSpecFiles/node_modules/@typespec/compiler/src/core/program.ts:575:7)
    at compile (file:///home/heaths/src/azure-sdk-for-rust/sdk/core/azure_core_test/TempTypeSpecFiles/node_modules/@typespec/compiler/src/core/program.ts:258:5)
    at compileOnce (file:///home/heaths/src/azure-sdk-for-rust/sdk/core/azure_core_test/TempTypeSpecFiles/node_modules/@typespec/compiler/src/core/cli/actions/compile/compile.ts:65:21)
    at compileAction (file:///home/heaths/src/azure-sdk-for-rust/sdk/core/azure_core_test/TempTypeSpecFiles/node_modules/@typespec/compiler/src/core/cli/actions/compile/compile.ts:31:5)

That is to say, these changes appear to be correct. The TypeSpec is just using something our emitter doesn't support yet.

/cc @jhendrixMSFT