Update GDS end-to-end figure (#1465)

### Description
The last figure may cause confusion since GDS may not affect
performance. The reason why it shows GDS looks needs fewer epochs to
achieve the same result is that the training didn't set deterministic,
so there may be little difference. Remove the last figure.

### Checks
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [ ] Avoid including large-size files in the PR.
- [ ] Clean up long text outputs from code cells in the notebook.
- [ ] For security purposes, please check the contents and remove any
sensitive info such as user names and private key.
- [ ] Ensure (1) hyperlinks and markdown anchors are working (2) use
relative paths for tutorial repo files (3) put figure and graphs in the
`./figure` folder
- [ ] Notebook runs automatically `./runner.sh -t <path to .ipynb file>`

Signed-off-by: KumoLiu <[email protected]>

Author: KumoLiu