Add network to mixpanel metrics

[jribbink]

Closes #1863

Description

Adds value of the network flag to metrics

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For contributor use:

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 28.55%. Comparing base (f529b1f) to head (e02d00f).

Files with missing lines	Patch %	Lines
internal/command/command.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1864      +/-   ##
==========================================
- Coverage   28.55%   28.55%   -0.01%     
==========================================
  Files          95       95              
  Lines        6524     6525       +1     
==========================================
  Hits         1863     1863              
- Misses       4479     4480       +1     
  Partials      182      182              

Flag	Coverage Δ
unittests	28.55% <0.00%> (-0.01%)	⬇️

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