parser: fix parsing map value inside or expr (fix #12164)

[yuyi98]

This PR fix parsing map value inside or expr (fix #12164).

• Fix parsing map value inside or expr.
• Add test.

struct MyError {
  msg string
  code int
}

fn (my MyError) msg() string {
	return my.msg
}

fn (my MyError) code() int {
	return my.code
}

type MapString = map[string]string | int

fn f() ?MapString {
  return MyError{msg: 'String Error'}
}

fn main() {
  println(f() or { { 'abc': err.msg() } })
}

PS D:\Test\v\tt1> v run .
MapString({'abc': 'String Error'})

[spytheman]

Excellent work.