fix: Adjust 'next command' timestamp increment to 2 seconds

This commit modifies the "suggest next command" feature in
`scripts/gha/get_pr_review_comments.py`. The time added to the
last processed comment's timestamp (for the `--since` parameter
in the suggested command) has been changed from 1 second to 2 seconds.

This adjustment provides a slightly larger buffer to more reliably
exclude already seen comments when fetching subsequent comments,
addressing potential timestamp granularity or query resolution
behavior observed with the GitHub API. The `since` parameter for
the relevant API endpoint filters by `created_at`, and this change
is a heuristic improvement for that existing logic.

Author: google-labs-jules[bot]

scripts/gha/get_pr_review_comments.py

@@ -202,7 +202,7 @@ def main():
     if latest_created_at_obj:
         try:
             # Ensure it's UTC before adding timedelta, then format
-            next_since_dt = latest_created_at_obj.astimezone(timezone.utc) + timedelta(seconds=1)
+            next_since_dt = latest_created_at_obj.astimezone(timezone.utc) + timedelta(seconds=2)
             next_since_str = next_since_dt.strftime('%Y-%m-%dT%H:%M:%SZ')
 
             new_cmd_args = [sys.argv[0]]