Refactor scoped namespace accesses and clones in type check context

[tritao]

Description

So this is another incremental step towards a following PR with the initial collection context migration.

Refactor namespace access in type check context.
Remove clones from scoped namespace usage.
Simplify type-check context creation from a namespace.

No functional changes intended.

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).
• 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.