Fix: Don't run benchmark comment for forks

[dqii]

See: https://github.com/peter-evans/create-pull-request/blob/main/docs/concepts-guidelines.md#restrictions-on-repository-forks

[github-actions]

Benchmarks

metric	old	new	pct change
recall (after create)	-	0.740	-
recall (after insert)	-	0.784	-
select tps	-	3810.250	-
select latency (ms)	-	1.551	-
create latency (ms)	-	1444.288	-
insert latency (ms)	-	1.762	-
insert tps	-	567.020	-
disk usage (bytes)	-	6348800.000	-

[codecov]

Codecov Report

Merging #132 (dcb7253) into main (accceec) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #132   +/-   ##
=======================================
  Coverage   83.79%   83.79%           
=======================================
  Files          13       13           
  Lines        1086     1086           
  Branches      244      244           
=======================================
  Hits          910      910           
  Misses         78       78           
  Partials       98       98