DelInboundClientByEmail gated the runtime RemoveUser/DeleteUser (and its
push-plan resolution) on !emailShared. But Xray users are keyed by inbound
tag + email, so a client attached to two inbounds left its user live in the
running Xray of every inbound where the email was still shared by a sibling
inbound, until an Xray restart.
Decouple the per-inbound runtime removal from emailShared; keep emailShared
only for preserving the shared email-keyed client_traffics/IP rows.
MHSanaei