Add feature to check for ObjcProvider linker info availability

Some rulesets inspect linking information from `ObjcProvider` and fallback to `CcInfo` only if a rule doesn’t propagate an `ObjcProvider`. After `7.0.0-pre.20230724.1` a `ObjcProvider` will exist, but it won’t have any linking information set.

Signed-off-by: Brentley Jones <github@brentleyjones.com>

features.bzl

@@ -11,6 +11,8 @@ _cc = struct(
     # Note: In Bazel 6.3 the `grep_includes` parameter is optional and a no-op in the cc_common API
     # In future Bazel versions it will be removed altogether.
     grep_includes_is_optional = ge("6.3.0"),
+    # From 7.0.0-pre.20230724.1 on `ObjcProvider` no longer contains linking info
+    objc_linking_info_migrated = ge("7.0.0-pre.20230724.1"),
 )
 
 _external_deps = struct(
@@ -22,7 +24,7 @@ _external_deps = struct(
 _flags = struct(
     # This flag was renamed in https://github.com/bazelbuild/bazel/pull/18313
     allow_unresolved_symlinks = (
-        "allow_unresolved_symlinks" 
+        "allow_unresolved_symlinks"
         if ge("7.0.0-pre.20230628.2")
         else "experimental_allow_unresolved_symlinks"
     )