Add animated gif for 3B SpinQuant (#5763)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/5763

- Add animated gif for 3B SpinQuant
- Remove bf16 numbers, for now, until we verify.

bypass-github-export-checks
bypass-github-pytorch-ci-checks
bypass-github-executorch-ci-checks
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Reviewed By: helunwencser

Differential Revision: D63649777

fbshipit-source-id: c6372b04cf0d9178c1da881fd327af573b552458