[Vulkan] Added Lerp op
Summary:
Added Lerp operator for Vulkan
Added tests for Lerp op
Test Plan: buck run //xplat/caffe2:pt_vulkan_api_test_binAppleMac
Differential Revision: D36009646
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76544
Approved by: https://github.com/SS-JIA, https://github.com/osalpekar
