TypeArgument as enum to support const generics

[xunilrj]

Description

Continuation of #7044.
This PR converts TypeArgument to an enum to support "const generic" in the future. It is being done separately because it changes a lot of files.

No change in behaviour is expected.

Checklist

• I have linked to any relevant issues.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation where relevant (API docs, the reference, and the Sway book).
  • If my change requires substantial documentation changes, I have requested support from the DevRel team
• I have added tests that prove my fix is effective or that my feature works.
• I have added (or requested a maintainer to add) the necessary Breaking* or New Feature labels where relevant.
• I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• I have requested a review from the relevant team or maintainers.

[codspeed-hq]

CodSpeed Performance Report

Merging #7052 will not alter performance

_{Comparing xunilrj/type-argument-as-enum (1bf1e9e) with master (4eb0705)}

Summary

✅ 22 untouched benchmarks