Revert "cmd: mark convert command as deprecated"

[mstoykov]

This reverts commit 030d37d.

[na--]

For posterity, the rationale behind this decision is that the new external HAR converter still doesn't have full feature parity with the current built-in k6 HAR converter.

[codecov-io]

Codecov Report

Merging #1268 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1268      +/-   ##
==========================================
+ Coverage   75.42%   75.43%   +0.01%     
==========================================
  Files         150      150              
  Lines       10883    10883              
==========================================
+ Hits         8208     8210       +2     
+ Misses       2209     2207       -2     
  Partials      466      466

Impacted Files	Coverage Δ
cmd/convert.go	46.15% <ø> (ø)	⬆️
stats/cloud/collector.go	77.6% <0%> (+0.61%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3de91a1...1faf3f6. Read the comment docs.