fix: log/print exit error of deltachat-rpc-server (#5601)

see also #5599 (this logs that error atleast, but does not fix it yet)

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Co-authored-by: iequidoo <117991069+iequidoo@users.noreply.github.com>

deltachat-rpc-server/src/main.rs

@@ -29,6 +29,9 @@ async fn main() {
     // "For technical reasons, stdin is implemented by using an ordinary blocking read on a separate
     // thread, and it is impossible to cancel that read. This can make shutdown of the runtime hang
     // until the user presses enter."
+    if let Err(error) = &r {
+        log::error!("Fatal error: {error:#}.")
+    }
     std::process::exit(if r.is_ok() { 0 } else { 1 });
 }