Chore: Make kodiak merge message empty (#26069)

.kodiak.toml

@@ -8,11 +8,11 @@ block_on_neutral_required_check_runs = true
 blocking_labels = ["stat: needs QA", "Invalid PR Title"]
 prioritize_ready_to_merge =  true
 
-
 [merge.message]
-title = "pull_request_title" # default: "github_default"
-body = "pull_request_body" # default: "github_default"
+title = "pull_request_title"
+body = "empty"
 include_coauthors=true
+
 [merge.automerge_dependencies]
 versions = ["minor", "patch"]
 usernames = ["dependabot"]