Run host-less and hosted tests in separate project schemes

Default tuist test runs (no explicit --scheme) no longer mix app-hosted and host-less test bundles in the generated workspace aggregate scheme. When the autogenerated workspace scheme contains host-less unit test bundles, Tuist now runs the generated project test schemes that cover its test targets separately, and filters --test-targets and --skip-test-targets per split scheme so a request for one test target won’t accidentally run another. This avoids the xctest bootstrap crash that happened when the host-less bundle was launched in the app launch context.