api!: remove e2ee_enabled preference

The setting is already removed from the UIs,
but users who had it disabled previously have
no way to enable it. After this change
encryption is effectively always preferred.

src/config.rs

@@ -151,10 +151,6 @@ pub enum Config {
     /// setting up a second device, or receiving a sync message.
     BccSelf,
 
-    /// True if encryption is preferred according to Autocrypt standard.
-    #[strum(props(default = "1"))]
-    E2eeEnabled,
-
     /// True if Message Delivery Notifications (read receipts) should
     /// be sent and requested.
     #[strum(props(default = "1"))]
@@ -705,7 +701,6 @@ impl Context {
             Config::Socks5Enabled
             | Config::ProxyEnabled
             | Config::BccSelf
-            | Config::E2eeEnabled
             | Config::MdnsEnabled
             | Config::SentboxWatch
             | Config::MvboxMove