Fix CI and Regression workflows for MAC Arm64

[namannandan]

Description

The Mac CI and regression failures are being caused by the following reasons:

1. The macos-lastest github runner tag now points to arm64 based Mac.
2. PyTorch 2.3 has dropped support for x86 Mac.
3. The M1 mac github runners do not expose the GPU(MPS hardware)
   Add GPU Passthrough (Metal) for GitHub-hosted macOS runners actions/runner-images#7085
   GitHub Action: New M1 runner available to all plans, including open source 🚀 actions/runner-images#9254 (comment)

This PR fixes the above issues by:

1. Fixing the GPU detection logic when running on M1 Mac to fall back to CPU. Note that the Mac CI and Regression only runs on CPU, when running on the github runner. To run on MPS, a self hosted runner will need to be created.
2. Update CI and regression tests to run on both CPU only and MPS on M1 Mac

Type of change

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

Feature/Issue validation/testing

• Mac arm64 CI: https://github.com/pytorch/serve/actions/runs/8976048758/job/24652034356?pr=3128
• Mac arm64 Regression: https://github.com/pytorch/serve/actions/runs/8976048741/job/24652042161?pr=3128

[mreso]

LGTM