fix error logic for recovery password

Session/Onboarding/LoadAccountScreen.swift

@@ -86,9 +86,9 @@ struct LoadAccountScreen: View {
         } catch {
             if let decodingError = error as? Mnemonic.DecodingError {
                 switch decodingError {
-                    case .inputTooShort, .missingLastWord:
+                    case .inputTooShort:
                         errorString = "recoveryPasswordErrorMessageShort".localized()
-                    case .invalidWord, .verificationFailed:
+                    case .invalidWord:
                         errorString = "recoveryPasswordErrorMessageIncorrect".localized()
                     default:
                         errorString = "recoveryPasswordErrorMessageGeneric".localized()

SessionUtilitiesKit/Crypto/Mnemonic.swift

@@ -66,7 +66,7 @@ public enum Mnemonic {
     }
     
     public enum DecodingError : LocalizedError {
-        case generic, inputTooShort, missingLastWord, invalidWord, verificationFailed
+        case generic, inputTooShort, invalidWord, verificationFailed
     }
     
     public static func hash(hexEncodedString string: String, language: Language = .english) -> String {
@@ -118,7 +118,7 @@ public enum Mnemonic {
         
         // Check preconditions
         guard words.count >= 12 else { throw DecodingError.inputTooShort }
-        guard words.count == 12 else { throw DecodingError.generic }
+        guard !words.count.isMultiple(of: 3) else { throw DecodingError.generic }
         
         // Get checksum word
         let checksumWord = words.popLast()!