enable flatten operator

[jsirianni]

Description of Changes

Enable the flatten operator

Please check that the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• Add a changelog entry (for non-trivial bug fixes / features)
• CI passes

[djaglowski]

Log Files	Logs / Second	CPU Avg (%)	CPU Avg Δ (%)	Memory Avg (MB)	Memory Avg Δ (MB)
1	1000	1.3448508	-0.1378951	130.07193	-0.12310791
1	5000	5.0863476	-0.12055111	136.34537	-1.9861298
1	10000	10.4140625	+0.034546852	144.45407	-0.973053
1	50000	49.94508	+0.5508919	178.74771	+5.4310303
1	100000	101.984375	+1.5213089	227.32098	-12.622437
10	100	1.879361	-0.08615434	132.65652	-0.6678314
10	500	6.120755	+0.18959284	143.02681	+4.3496857
10	1000	11.879609	+0.46557713	146.8455	-0.057235718
10	5000	56.357716	+3.1505203	179.1673	-0.81074524
10	10000	106.59594	-3.62883	216.92955	-11.05159

[codecov]

Codecov Report

Merging #390 (0ea3140) into master (74fc7a1) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #390      +/-   ##
==========================================
- Coverage   73.25%   73.23%   -0.03%     
==========================================
  Files         124      124              
  Lines        7994     7994              
==========================================
- Hits         5856     5854       -2     
+ Misses       1640     1637       -3     
- Partials      498      503       +5     

Impacted Files	Coverage Δ
operator/builtin/output/newrelic/newrelic.go	72.73% <0.00%> (-1.65%)	⬇️
operator/builtin/input/file/file.go	79.06% <0.00%> (-1.57%)	⬇️
operator/builtin/output/otlp/otlp.go	68.13% <0.00%> (+3.30%)	⬆️

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[ericwholt]

Works great. I can now use flatten operator with this change.