zlog: Ensure log file is flushed (#28923)

Closes #ISSUE

Release Notes:

- N/A *or* Added/Fixed/Improved ...

crates/zed/src/reliability.rs

@@ -130,6 +130,7 @@ pub fn init_panic_hook(
         if let Some(panic_data_json) = serde_json::to_string_pretty(&panic_data).log_err() {
             log::error!("{}", panic_data_json);
         }
+        zlog::flush();
 
         if !is_pty {
             if let Some(panic_data_json) = serde_json::to_string(&panic_data).log_err() {