Remove unimplemented SetCrypted from DescriptorScriptPubKeyMan

src/wallet/scriptpubkeyman.h

@@ -503,8 +503,6 @@ private:
     KeyMap m_map_keys GUARDED_BY(cs_desc_man);
     CryptedKeyMap m_map_crypted_keys GUARDED_BY(cs_desc_man);
 
-    bool SetCrypted();
-
     //! keeps track of whether Unlock has run a thorough check before
     bool m_decryption_thoroughly_checked = false;