TG proxy fix after explicit get_updates_request

[emliunix]

.get_updates_proxy(proxy) and explicit .get_updates_request(get_updates_request) cannot coexist.

So need to set proxy on get_updates_request directly.

And I noticed telegram message sending are now scripts. And here's the design concern for the scripts:

• they should support proxy too.
• but being general scripts means they should support source proxy from wherever the caller wants
• bub itself also source proxy from multiple locations (BUB_TELEGRAM_PROXY, HTTPS_PROXY, system settings, etc)
• we can have the script support explicit argument for passing proxy, but that's a distraction for the agent's context
• so I prefer to setup bub process's env vars to naturally let the script call inherit the BUB_TELEGRAM_PROXY env var

I'll leave the scripts unchanged for now and the PR in draft for more design input.

[frostming]

Superseded by #200