[Docs][Bug] Image missing for UMA tutorial

[StrongerXi]

The image in this section of the UMA tutorial is missing.

Root cause seems to be that it's missing in the corresponding resource url.

[qzylalala]

URL: https://raw.githubusercontent.com/apache/tvm-site/main/images/tutorial/uma_vanilla_block_diagram.png
But still not found

[lhutton1]

Closing as this should be fixed by #13624, the docs may take a bit of time to bring in the change. Feel free to reopen if the problem persists.