[Bug]: Versioning decorator can not be applied to spread declarations

[allenjzhang]

Describe the bug

Versioning decorator should be able to apply to spread model.

Reproduction

model Employee is TrackedResource<EmployeeProperties> {
  /** Name of employee */
  @pattern("^[a-zA-Z0-9-]{3,24}$")
  @key("employeeName")
  @path
  @segment("employees")
  name: string;

  @added(Versions.`2023-10-01-preview`)   <-- Unable to add this really limited usages of spread model
  ...ManagedServiceIdentityProperty;
}

Checklist

• Follow our Code of Conduct
• Check that there isn't already an issue that request the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion.
• The provided reproduction is a minimal reproducible example of the bug.

[markcowl]

@markcowl add an issue to typespec-azure on the arm-specific issue