PYSEC-2026-3196 Missing validation causes denial of service via `StagePeek`

Impact The implementation of tf.rawops.StagePeek does not fully validate the input arguments. This results in a CHECK-failure which can be used to trigger a denial of service attack: python import tensorflow as tf index = tf.constant, shape=0, dtype=tf.int32 tf.rawops.StagePeekindex=index,...