Suppress Webclient error notification on a per-request basis
There are cases when a request technically results in an error response (4xx or 5xx) but the Webclient should not present that error to the user by the means of a notification box:
There are at least 2 such cases:
- The user types a Lucene search query which due to the nature of the Search dialog's incremental approach may be (temporarily) syntactical incorrect. See #274 (comment 11221)
- The user enters invalid credentials in the Login dialog.