web: clear out selecteds list after an API event to ensure a fresh copy of the policies-to-delete list (#8125)

* web: clear out selecteds list after an API event to ensure a fresh copy of the policies-to-delete list

* Prettier had opinions.

* web: A better fix

This fix creates a new property of Table, 'clearOnRefresh', which
automatically empties the `selectedElements` list when an EVENT_REFRESH
event completes.  Set this flag on any table that uses the
`selectedElements` list for bulk deletion; this ensures that stale
data in the `selectedElements` list will not persist and interfere
with future deletion events.

web/src/user/user-settings/mfa/MFADevicesPage.ts

@@ -25,6 +25,7 @@ export class MFADevicesPage extends Table<Device> {
     userSettings?: UserSetting[];
 
     checkbox = true;
+    clearOnRefresh = true;
 
     async apiEndpoint(): Promise<PaginatedResponse<Device>> {
         const devices = await new AuthenticatorsApi(DEFAULT_CONFIG).authenticatorsAllList();

web/src/user/user-settings/tokens/UserTokenList.ts

@@ -29,6 +29,7 @@ export class UserTokenList extends Table<Token> {
 
     expandable = true;
     checkbox = true;
+    clearOnRefresh = true;
 
     @property()
     order = "expires";