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

src/webxdc/webxdc_tests.rs

@@ -124,6 +124,23 @@ async fn test_send_invalid_webxdc() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_set_draft_invalid_webxdc() -> Result<()> {
+    let t = TestContext::new_alice().await;
+    let chat_id = create_group_chat(&t, ProtectionStatus::Unprotected, "foo").await?;
+
+    let mut instance = create_webxdc_instance(
+        &t,
+        "invalid-no-zip-but-7z.xdc",
+        include_bytes!("../../test-data/webxdc/invalid-no-zip-but-7z.xdc"),
+    )?;
+
+    // draft should not fail
+    chat_id.set_draft(&t, Some(&mut instance)).await?;
+    chat_id.get_draft(&t).await.unwrap();
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_send_special_webxdc_format() -> Result<()> {
     let t = TestContext::new_alice().await;