[Bug]: @tag decorator not support tag object

[skywing918]

Describe the bug

{The problematic object} failed to {describe the problem}.

TSP

import "@typespec/openapi3";

using TypeSpec.OpenAPI;
@tag("Tags")
@tag("Tagging")
@service
namespace PetStore;
op readxxx(): string;

Actual Specification

tags:
  - name: Tags
  - name: Tagging

Expected Specification

https://spec.openapis.org/oas/v3.0.0#tag-object
The Tag object have the following fixed files

name | REQUIRED. The name of the tag.
description | A short description for the tag. CommonMark syntax MAY be used for rich text representation.
externalDocs | Additional external documentation for this tag.

tags:
 - name: Tags
   description: Tags infos
 - name:Tagging
``` description: Tagging infos


### Reproduction

1. `git clone [https://github.com/skywing918/typespec-workaround.git`](https://github.com/skywing918/typespec-workaround.git%60)
2. `tsp compile tags.tsp`
3. Open `/tsp-output/@typespec/openapi3` to get the result

### 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.

[timotheeguerin]

Duo of #2220