fix: Prevent if and for from parsing constructor expressions

[jfecher]

Description

Problem*

In the code:

if x {
    y
} else {
    z
}

The parser would parse an expression for the if condition and x { y } is a valid constructor expression using the shorthand field syntax. I've resolved this to more closely follow rust's official grammar (https://doc.rust-lang.org/reference/expressions/if-expr.html) in which constructor expressions are forbidden as part of an if condition:

Note the "except struct expression" subscript.

Resolves #1915 and #152

Summary*

Unfortunately this PR is quite messy. I'm not sure of a good way to clean it up at the moment without duplicating the expression parser. Chumsky requiring us to pass each recursive parser as a parameter makes it quite a bit more verbose.

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.