Compiler infinite loop with instantiation of templated string

[bterlson]

Describe the bug

Compiler loops and crashes with this sample

Reproduction

import "@typespec/openapi";
import "@typespec/openapi3";
using OpenAPI;

@extension("x-amazon-apigateway-integration", { 
    credentials: typeof "arn:aws:iam::${accountId}:role/api-gateway-step-function"
})
model Foo<accountId extends valueof string> {}

model Bar {
  x: Foo<"hello">;
}

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• The provided reproduction is a minimal reproducible example of the bug.