fix: Perform occurs check before binding function types

[jfecher]

Description

Problem*

Resolves #2009

Summary*

Previously when type checking function calls if the function was an unbound type variable we'd bind the type variable without performing an occurs check first. This lead to us creating infinitely recursive types such as a = (fn(a) -> ()) as in the issue above. Since we should never bind without performing an occurs check in general, I've made a helper function to help avoid this in the future.

Documentation

• This PR requires documentation updates when merged.

  • I will submit a noir-lang/docs PR.
  • I will request for and support Dev Rel's help in documenting this PR.

Additional Context

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.