[omdb] de-flake and tidy up sp_ereport_ingester status

[hawkw]

There's currently a test flake in the test_omdb_success_cases test due to the output from the sp_ereport_ingester background task (see #8979). This is because the status output for that test will depend on the number of MGSes and simulated SPs that are currently present when the test runs. In particular, this means that the output may differ based on whether the test is run in isolation or as part of a run including other tests, as it's likelier that Nexus will have discovered the simulated SPs when other tests have already run.

This branch fixes the flake by adding additional redaction configs for this task's status output. We now redact all the numbers in the output. Additionally, we must redact the sections listing individual SPs and their ereport counts, and the section listing top level errors. Since these sections are only shown when the lists of SPs or errors are non-empty (the output looks weird if we print an empty section heading for them), we don't use the existing Redactor::section method. This method will replace the indented contents of a section with the string <{section_name}_REDACTED>. That's sufficient when just the section contents are variable, but in this case, the sections may or may not be present depending on whether MGS was up, so we would get either a redacted section (if it was present) or nothing. Therefore, I've added a new Redactor::totally_annihilate_section method that removes a section along with its heading for use in this case. It's a bit of a shame to totally wipe these sections from the output, but it seemed like the best choice under the circumstances.

I've also tweaked the status output a little bit to fix some cases where numbers in the output were not aligned the way I wanted them to be, and to make it slightly friendlier to the redactor by removing totals from the headings of redacted sections.

Fixes #8979

[zeeshanlakhani]

ack. this for the writeup on the format changes too.