Don't bundle libtpu in nightly (#6885)
Summary:
Pallas depends on JAX to run, and JAX by default will use the system libtpu and won't use our own bundled libtpu. In order to have JAX and PyTorch/XLA run side by side, we will need to have them use the same libtpu. The solution could either be setting the TPU_LIBRARY_PATH or having both of them use the same system libtpu. The latter yields a much better UX.
Test Plan:
N.A.
