fix(gateway): add lazy_deps.ensure() to slack, matrix, dingtalk, feishu adapters (#25014)

Only Discord and Telegram had lazy-install hooks in their
check_*_requirements() functions. The remaining four platforms that were
moved to lazy_deps (Slack, Matrix, DingTalk, Feishu) would just return
False immediately if their packages weren't pre-installed — no attempt
to install them at runtime.

This means even with the .venv permissions fix (#24841), these four
platforms would still fail to load in Docker (or any fresh install)
unless the user manually ran pip install.

Add the same lazy_deps.ensure() pattern to all four, matching the
existing Discord/Telegram implementation.

tools/lazy_deps.py

@@ -120,6 +120,7 @@ LAZY_DEPS: dict[str, tuple[str, ...]] = {
     "platform.slack": (
         "slack-bolt==1.27.0",
         "slack-sdk==3.40.1",
+        "aiohttp==3.13.3",
     ),
     "platform.matrix": (
         "mautrix[encryption]==0.21.0",