[TCGC] Have helper functions to tell isIntKinds and isFloatKinds

[haolingdong-msft]

TCGC provides helper functions to tell isBuiltInKind, but does not provide isFloatKind and isIntKind, and the related enums SdkIntKindsEnum and SdkFloatKindsEnum are not exposed as well.
But clients sometimes need to do type mapping for specific int types or float types, e.g.

export function getDurationFormatFromSdkType(type: SdkDurationType): DurationSchema["format"] {
  let format: DurationSchema["format"] = "duration-rfc3339";
  // duration encoded as seconds
  if (type.encode === "seconds") {
    if (isSdkIntKind(type.wireType.kind)) {
      format = "seconds-integer";
    } else if (isSdkFloatKind(type.wireType.kind)) {
      format = "seconds-number";
    } else {
      throw new Error(`Unrecognized scalar type used by duration encoded as seconds: '${type.kind}'.`);
    }
  }
  return format;
}

If client write their own helper function, the type could be inconsistent with TCGC. So I wonder if TCGC can provide this kind of helper functions.