feat(cli-test): update traces for env to SLACK_TRACE_ENV_

[mwbrooks]

Summary

This pull request updates the (unused) test traces for the env command from SLACK_TRACE_VARIABLES_ to SLACK_TRACE_ENV_.

These traces are updated because the Slack CLI has also updated it's env traces to be SLACK_TRACE_ENV_.

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.89%. Comparing base (767a8a0) to head (ba12c1f).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2136   +/-   ##
=======================================
  Coverage   91.89%   91.89%           
=======================================
  Files          38       38           
  Lines       10320    10320           
  Branches      649      649           
=======================================
  Hits         9484     9484           
  Misses        824      824           
  Partials       12       12           

Flag	Coverage Δ
cli-hooks	95.24% <ø> (ø)
cli-test	94.48% <100.00%> (ø)
oauth	77.39% <ø> (ø)
socket-mode	61.82% <ø> (ø)
web-api	96.88% <ø> (ø)
webhook	96.65% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

[zimeg]

Sweet! It's nice that this matches the command now and super glad we can land this before #2097 is released 🙏

[mwbrooks]

Thanks for pointing out that we haven't released #2097! It's a great opportunity to tighten up these traces before we go live.