Undo API-breaking change to go_sdk experiments attribute (#4210) **What type of PR is this?** Bug fix, see https://github.com/bazel-contrib/rules_go/pull/4022#issuecomment-2566548860 **What does this PR do? Why is it needed?** Reverts the behavior to the API while keeping the optimization **Which issues(s) does this PR fix?** Fixes # **Other notes for review**