Bump KerasNLP version to 15.1 and update symbols (keras-team#1933)

We've made a number of name changes to accommodate multi-modal
models with a lot more task types.

Author: mattdangerw

scripts/autogen.py

@@ -47,7 +47,7 @@
     "keras": f"{KERAS_TEAM_GH}/keras/tree/v3.5.0/",
     "keras_tuner": f"{KERAS_TEAM_GH}/keras-tuner/tree/v1.4.7/",
     "keras_cv": f"{KERAS_TEAM_GH}/keras-cv/tree/v0.9.0/",
-    "keras_nlp": f"{KERAS_TEAM_GH}/keras-nlp/tree/v0.14.4/",
+    "keras_nlp": f"{KERAS_TEAM_GH}/keras-nlp/tree/v0.15.1/",
     "tf_keras": f"{KERAS_TEAM_GH}/tf-keras/tree/v2.17.0/",
 }
 USE_MULTIPROCESSING = False