message: Add dummy rule for keras_preprocessing so that it can be swapped by copybara in OSS.
diff: @@ -666,6 +666,14 @@ py_library(
  visibility = ["//visibility:public"],
  )
  +py_library(
  + name = "expect_keras_preprocessing_installed",
  + # This is a dummy rule used as a keras_preprocessing dependency in open-source.
  + # We expect keras_preprocessing to already be installed on the system, e.g. via
  + # `pip install keras_preprocessing`
  + visibility = ["//visibility:public"],
  +)
  +
  py_library(
  name = "expect_numpy_installed",
  # This is a dummy rule used as a numpy dependency in open-source.
  