logtail: default to 2s log flush delay on all platforms

Per chat. This is close enough to realtime but massively reduces
number of HTTP requests. (which you can verify with
TS_DEBUG_LOGTAIL_WAKES and watching tailscaled run at start)

By contrast, this is set to 2 minutes on mobile.

Change-Id: Id737c7924d452de5c446df3961f5e94a43a33f1f
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f