feat(forge coverage): support running coverage on a test suite with failing tests

[Simon-Busch]

Component

Forge

Describe the feature you would like

Since the introduction of #8268, we need to have all passing tests to generate the coverage summary or lcov.

I understand the intend, however in some case, it would be great to be able to generate the coverage even with a few failing tests.

Ex: I'm working on an engagement for a customer, on a specific part of the architecture, there are a couple of failing tests on the otherside, I would love to be able to still generate the coverage report with a specific flag.

ex: forge coverage --report lcov --accept-failure

Additional context

No response

[grandizzy]

@Simon-Busch cannot you just use different branches and run coverage for tests related to specific part of the architecture?