Fix crash with LibreTranslate server setting selection and remove delisted vern server

Broken after the settings refactor

Changelog-Fixed: Fix crash with LibreTranslate server setting selection and remove delisted vern server

damus/Models/LibreTranslateServer.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-enum LibreTranslateServer: String, CaseIterable, Identifiable {
+enum LibreTranslateServer: String, CaseIterable, Identifiable, StringCodable {
     var id: String { self.rawValue }
 
     struct Model: Identifiable, Hashable {
@@ -17,9 +17,19 @@ enum LibreTranslateServer: String, CaseIterable, Identifiable {
         var url: String?
     }
 
+    func to_string() -> String {
+        return rawValue
+    }
+
+    init?(from string: String) {
+        guard let libreTranslateServer = LibreTranslateServer(rawValue: string) else {
+            return nil
+        }
+        self = libreTranslateServer
+    }
+
     case argosopentech
     case terraprint
-    case vern
     case custom
 
     var model: Model {
@@ -28,8 +38,6 @@ enum LibreTranslateServer: String, CaseIterable, Identifiable {
             return .init(tag: self.rawValue, displayName: "translate.argosopentech.com", url: "https://translate.argosopentech.com")
         case .terraprint:
             return .init(tag: self.rawValue, displayName: "translate.terraprint.co", url: "https://translate.terraprint.co")
-        case .vern:
-            return .init(tag: self.rawValue, displayName: "lt.vern.cc", url: "https://lt.vern.cc")
         case .custom:
             return .init(tag: self.rawValue, displayName: NSLocalizedString("Custom", comment: "Dropdown option for selecting a custom translation server."), url: nil)
         }

damus/Models/UserSettingsStore.swift

@@ -157,7 +157,7 @@ class UserSettingsStore: ObservableObject {
         }
     }
 
-    @Setting(key: "libretranslate_server", default_value: .vern)
+    @StringSetting(key: "libretranslate_server", default_value: .terraprint)
     var libretranslate_server: LibreTranslateServer
     
     @Setting(key: "libretranslate_url", default_value: "")