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/e2ee.rs

@@ -4,10 +4,8 @@ use std::io::Cursor;
 
 use anyhow::Result;
 use mail_builder::mime::MimePart;
-use num_traits::FromPrimitive;
 
 use crate::aheader::{Aheader, EncryptPreference};
-use crate::config::Config;
 use crate::context::Context;
 use crate::key::{SignedPublicKey, load_self_public_key, load_self_secret_key};
 use crate::pgp;
@@ -21,9 +19,7 @@ pub struct EncryptHelper {
 
 impl EncryptHelper {
     pub async fn new(context: &Context) -> Result<EncryptHelper> {
-        let prefer_encrypt =
-            EncryptPreference::from_i32(context.get_config_int(Config::E2eeEnabled).await?)
-                .unwrap_or_default();
+        let prefer_encrypt = EncryptPreference::Mutual;
         let addr = context.get_primary_self_addr().await?;
         let public_key = load_self_public_key(context).await?;