Adds SessionScopeResources.PublicChannelTeamIDs: every public channel on
the listed teams, whether or not the team is open, so the plugin can
always include the triggering channel's team. Compliance mode turns it off;
deleted and policy-enforced teams and channels stay excluded.
SessionScopeAllowsChannel now takes SessionScopeLimits so compliance mode
and join_public_teams can limit the two public-channel grants separately.
Flags channel/team lookups by name, channel stats, pinned posts, post
reactions and user search for scoped sessions, each gated by the scope.
Co-authored-by: Christopher Speller <crspeller@users.noreply.github.com>