refactor: build_body_file(): Remove guessing mimetype by file extension

Guessing mimetype is already done in `chat::prepare_msg_blob()`.

src/mimefactory.rs

@@ -27,7 +27,7 @@ use crate::key::self_fingerprint;
 use crate::key::{DcKey, SignedPublicKey};
 use crate::location;
 use crate::log::{info, warn};
-use crate::message::{self, Message, MsgId, Viewtype};
+use crate::message::{Message, MsgId, Viewtype};
 use crate::mimeparser::{SystemMessage, is_hidden};
 use crate::param::Param;
 use crate::peer_channels::create_iroh_header;
@@ -1821,18 +1821,11 @@ async fn build_body_file(context: &Context, msg: &Message) -> Result<MimePart<'s
         _ => file_name,
     };
 
-    /* check mimetype */
-    let mimetype = match msg.param.get(Param::MimeType) {
-        Some(mtype) => mtype.to_string(),
-        None => {
-            if let Some((_viewtype, res)) = message::guess_msgtype_from_suffix(msg) {
-                res.to_string()
-            } else {
-                "application/octet-stream".to_string()
-            }
-        }
-    };
-
+    let mimetype = msg
+        .param
+        .get(Param::MimeType)
+        .unwrap_or("application/octet-stream")
+        .to_string();
     let body = fs::read(blob.to_abs_path()).await?;
 
     // create mime part, for Content-Disposition, see RFC 2183.

src/mimefactory/mimefactory_tests.rs

@@ -12,6 +12,7 @@ use crate::chatlist::Chatlist;
 use crate::constants;
 use crate::contact::Origin;
 use crate::headerdef::HeaderDef;
+use crate::message;
 use crate::mimeparser::MimeMessage;
 use crate::receive_imf::receive_imf;
 use crate::test_utils::{TestContext, TestContextManager, get_chat_msg};