[CSApply] Perform a regular coerceToType when adjusting types for @preconcurrency.

[hborla]

In a case like this:

class Request {
  @preconcurrency let identifier: (any Sendable)? = nil
}

func test(request: Request) {
  let _ = request.identifier
}

CSApply ends up in adjustTypeForDeclReference attempting to coerce any Sendable to Any. A regular coerceToType can handle this adjustment, so do that instead of asserting / silently failing.

[hborla]

@swift-ci please smoke test

[xedin]

LGTM!