remove smithy4sRenderOptics setting from plugins

[yisraelU]

and the corresponding sbt-test module
closes #1537

PR Checklist (not all items are relevant to all PRs)

• Added documentation
• Updated changelog

[kubukoz]

Do we still have tests that utilize the optics being generated conditionally?

[yisraelU]

Do we still have tests that utilize the optics being generated conditionally?

I thought so , I will verify

[kubukoz]

Confirmed, we have:

• tests in renderer that assert on the exact rendered code (btw it would be a nice usecase for https://github.com/siriusxm/snapshot4s), these ensure that we don't just generate optics for everything
• tests that involve using actual generated optics on the types that got them, these ensure that the config isn't ignored

so I think we're good.

[kubukoz]

thought: I would consider dropping smithy4sWildcardArgument too, we should use * and ask people to enable -Xsource:3 or -Xsource:3-cross.