SCHED-1943: Fix OpenTelemetry Collector JSON parsing errors for slurm_scripts

[Uburro]

Problem

The jail-logs otel collector spams error-level logs with huge stacktraces: invalid character '\u0000' looking for beginning of value. Check output files on the shared jail FS are truncated and rewritten in place by check_runner.py, so the collector (tailing from another node) can read partially flushed lines with zero-filled tails, and the json_parser fails on them. Logs are still delivered — it's pure noise. Reproduces on some clusters (m42-h200, ami-labs) depending on storage/timing.

Solution

Hardened the parse_json_body operator in the jail-logs collector config:

• extended the if guard to skip lines containing NUL bytes;
• added on_error: send_quiet so any other parse failure sends the entry unparsed and logs at debug instead of error.

The parser is kept because it feeds slurm_run_status / slurm_run_resolution log labels (added in #2125).

Testing

• make helmtest
• helm template — verified the rendered operator config is valid and contains the new condition and on_error.
• on the live cluster

Release Notes

Fix: jail-logs otel collector no longer emits error-level noise when reading partially flushed health check output files containing NUL bytes.