Remove the capping on the means in GMM attention.
Remove the capping on the means in GMM attention.

The current capping is based on Tensor dimension, rather than the actual length of the sequence. This is problematic as it depends on other examples in the same batch, or the overall padding strategy.

PiperOrigin-RevId: 277656839

tensorflow/lingvo,tensorflow/lingvo,tensorflow/lingvo,tensorflow/lingvo