Add vl.xrpl.vision to validators-example.txt

[xrplvision]

Add the list provider vl.xrpl.vision (xrpl.vision) to validators-example.txt and include the keys.

[mov-bx-0xb800]

xrpl.vision was recently introduced on the network not long ago. I suggest giving some time for the author to prove its relevance and security, until this UNL is "recommended"

[Bronek]

I recommend waiting until https://github.com/XRPLF/rippled/pull/5112 is merged and released ; without this change, any additional UNL publisher will reduce the security of the UNL system

[mov-bx-0xb800]

rel. to @Bronek's comment: https://github.com/XRPLF/rippled/pull/5112#issuecomment-2463615278