As required by https://github.com/isaac-sim/IsaacLab/pull/2962 and
vulnerabilities in torch 2.5.1, this change updates torch to 2.7.0
during the installation of Isaac Lab.

Although inconsistent with Isaac Sim 4.5 (still on torch 2.5.1), Isaac
Lab should work fine with 2.7.0+cu128. This update will also allow us to
have better support for blackwell GPUs.

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- Bug fix (non-breaking change which fixes an issue)
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