Prevent large dictionaries being placed in events.data

[graepaul]

Summary

• This is to fix the following issue that was reported by users
  • Exception in post_check_top: 1 validation error for Event
    data
    Value error, Data must be below 100KB in size [type=value_error,
    input_value={'mem_free': '<epoch_time...parent': 'memoryplugin'}, input_type=dict]
• Also some other edits to remove model_dumps so that data is not large.

Test plan

• pytest test/unit
• pytest test/functional (if applicable)
• pre-commit run --all-files

Checklist

• Added/updated tests (or explained why not)
• Updated docs/README if behavior changed
• No secrets or credentials committed