Allow `optional_implicit_deps` and `required_implicit_deps` to be set on an `xcode_swift_toolchain` target.
Allow `optional_implicit_deps` and `required_implicit_deps` to be set on an `xcode_swift_toolchain` target.

PiperOrigin-RevId: 347841955
(cherry picked from commit 875de9fc0b08bedb30e7de2e3f992cd9f818e40d)

bazelbuild/rules_swift,bazelbuild/rules_swift