chore(common): remove unnecessary `ReportKind` abstraction

[mablr]

I propose to remove struct ReportKind as it is a redundant abstraction layer over shell.

foundry/crates/common/src/reports.rs

Line 6 in 91cfab4

pub enum ReportKind {

It is only used in SizeReport, TestSummaryReport, and GasReport. Other forge report types are already using shell directly (e.g. storage, selectors...).

This straightforward simplification represents a nice initial step towards refactoring and unifying the display of all Forge report types (#11473 as follow-up).

If you think it's relevant, I would be happy to propose a PR 😊

[zerosnacks]

It appears many of us prefer the direct check against shell. I would be in favor of removing the abstraction.

Thanks!