fix: clean up, so we don't send empty metrics report

[nickchen]

Proposed changes

• clean up, use generated enum instead of 0 int for proto type
• check for non-empty report before sending, this should fix the empty report on the consumer side

Checklist

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• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md)

[oliveromahony]

@aphralG has a fix for this which prevents the calculation of the empty metrics reports instead of checking for empty data and discarding. Let's wait for that PR instead of merging this, thanks

[sanathkumarbs]

Likely should close this as we have #82