readyset-logictest: Don't output entire query in Antithesis details

The actual failure reason is at the beginning of the message, and
usually followed by the entire failing query. Since that can get massive
when fuzzing, and the query gets written out as part of the script, it's
useless to include the full message in the details.

Change-Id: I6a6a69646df7eb9a006a1d384c9610c6fb1e3946
Reviewed-on: https://gerrit.readyset.name/c/readyset/+/9722
Reviewed-by: Sandaruwan Gunathilake <sandaruwan@readyset.io>
Tested-by: Buildkite CI

Author: mvzink

readyset-logictest/src/main.rs

@@ -643,7 +643,9 @@ impl Fuzz {
                     json!({
                         "failure_kind": "failing_query",
                         "extract_file": path.to_string_lossy(),
-                        "reason": reason.message(),
+                        // Truncate reason (which includes the query) because especially large
+                        // queries are useless to log here. The query will be in the file.
+                        "reason": reason.message()[..256],
                     }),
                 )
             }