"Null" for credentials

[KUGDev]

In the plugin, a situation is possible when credentials are broken (for example, KeePass gives IndexOutOfBounds or its database is suddenly deleted).
It is necessary to provide the ability in the plugin to set the credits to a null value so that the plugin's operation is not disrupted. In addition, it is necessary to provide for the restoration of credits in the event that the kdbx file is not completely broken. To do this, you need to introduce the "Repair connection" button on the connections that are broken

Reimplement the taking of parameters from connections