[Bug][http-client-js] encode to number didn't handle correctly

### Describe the bug
Regarding the spector test cases - [specs/encode/numeric](https://github.com/microsoft/typespec/blob/main/packages/http-specs/specs/encode/numeric/main.tsp), the exposed type and serialzied type on the wire are different. Currently emitter just generates exposed one the same as the wire one directly. So generated codes are not correct and [relevant test cases are skipped now](https://github.com/microsoft/typespec/blob/fba94cc316febb05deb166e3bbd8a41bcbd2cadd/packages/http-client-js/test/e2e/http/encode/numeric/main.test.ts).

### Reproduction

NA

### Checklist

- [x] Follow our [Code of Conduct](https://github.com/microsoft/typespec/blob/main/CODE_OF_CONDUCT.md)
- [x] Check that there isn't already an issue that request the same bug to avoid creating a duplicate.
- [x] Check that this is a concrete bug. For Q&A open a [GitHub Discussion](https://github.com/Microsoft/typespec/discussions).
- [x] The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) of the bug.