build: Using telescope gen code instead of ts-proto

[Zetazzz]

I'm updating Hands on exercise, Cosmjs-adv section with Using telescope gen code instead of ts-proto and I found I also need to update the code here. And I think I also need to update the code gen part in branches derived from this branch(I'll do that after this change's reviewed)

And I also need to update the client project in another PR with generated code using telescope

Thank you very much!

[xavierlepretre]

Thank you. I will not make it part of this code just yet. And when I do, it will not be just a merge of this PR because I have to keep the succession of commits "clean". So I take your work then reorder and squash.