spam quarantine: avoid full store reload on single-element actions

spam quarantine: avoid full store reload on single-element actions

A store load may require several seconds to complete, which can get
frustrating fast.

For single actions we have a callback which gets only executed on a
successful API call, so we can just remove the entry there directly
from the in-memory store.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>