Fix(jsonrpc): Do not error on missign webxdc info (#6866)

When an invalid webxdc is set as draft, json-rpc's `get_draft` fails,
because `get_webxdc_info` which it calls, fails because the zip reader
can not read a non-zip file. With this change, any error occurring in
`get_webxdc_info` is ignored and the None-variant is returned instead. I
also added a test, that setting invalid xdcs is draft is fine core-wise
and checked that the input field stays responsive when a fake.xdc
produced like in #6826 is added to draft

close #6826

deltachat-jsonrpc/src/api/types/message.rs

@@ -8,6 +8,7 @@ use deltachat::chat::ChatVisibility;
 use deltachat::contact::Contact;
 use deltachat::context::Context;
 use deltachat::download;
+use deltachat::log::LogExt as _;
 use deltachat::message::Message;
 use deltachat::message::MsgId;
 use deltachat::message::Viewtype;
@@ -143,7 +144,10 @@ impl MessageObject {
         let override_sender_name = message.get_override_sender_name();
 
         let webxdc_info = if message.get_viewtype() == Viewtype::Webxdc {
-            Some(WebxdcMessageInfo::get_for_message(context, msg_id).await?)
+            WebxdcMessageInfo::get_for_message(context, msg_id)
+                .await
+                .log_err(context)
+                .ok()
         } else {
             None
         };