Qualcomm AI Engine Direct - ESRGAN Enablement (#3751)

Summary:
- OSS model enablement: esgan (https://github.com/ai-forever/Real-ESRGAN)
- support upsample_nearest2d / pixel_unshuffle / leaky_relu / prelu
- test cases for newly added operators

Pull Request resolved: https://github.com/pytorch/executorch/pull/3751

Reviewed By: kirklandsign

Differential Revision: D57896517

Pulled By: cccclai

fbshipit-source-id: 12e7911ef28dbb15604ada4fe5bc6f848b819eab