Resolves tuist#454

- All `FrameworkNodes` (i.e. prebuilt frameworks) were being embedded regardless of their linkage
- This check was redundant as there was a more general check for `PrecompiledNode` which happens to be the super class of `FrameworkNode` which took into account the framework linkage
- To resolve this issue it was suffice to remove the redundant check

Test Plan:

- Generate `fixtures/ios_app_with_static_frameworks` via running `tuist generate`
- Verify the generated project doesn't embed `PrebuiltStaticFramework`
- Verify the generated project builds successfully