fix: route Teams send() through SOCKS5 proxy

Teams send() used urllib.request.urlopen directly, bypassing the SOCKS5
proxy. Replace with derp.http.urlopen to match all other outbound HTTP.

src/derp/teams.py

@@ -14,6 +14,7 @@ import urllib.request
 from dataclasses import dataclass, field
 from pathlib import Path
 
+from derp import http
 from derp.bot import _TokenBucket
 from derp.plugin import TIERS, PluginRegistry
 from derp.state import StateStore
@@ -389,7 +390,7 @@ class TeamsBot:
         )
         loop = asyncio.get_running_loop()
         try:
-            await loop.run_in_executor(None, urllib.request.urlopen, req)
+            await loop.run_in_executor(None, http.urlopen, req)
         except Exception:
             log.exception("teams: failed to send via incoming webhook")