UI Option to View and Clear Cached Gateway Fix-Up Overrides

NetBrain currently does not provide a way to view or remove a manually set Fix-Up Gateway once it has been cached for path calculation. As a result, a one-time manual override can continue to be applied indefinitely, even after the underlying resolution issue no longer exists, with no UI-based way to clear it. This enhancement would add a UI option to view and delete previously cached Fix-Up Gateway entries, and would optionally allow a manually selected gateway to be applied one time without being saved to cache. Customers would gain better control over path calculation accuracy and avoid outdated manual overrides silently affecting future results.