chore: release slack-cli v4.8.0

[slack-cli-releaser]

Summary

Release v4.8.0.

Testing

• Confirm unit tests and E2E tests are passing on the branch.
• Confirm unit tests and E2E tests are passing on this PR.
• Confirm the dev-build includes all commits since last release.
• Review open issues or PRs on the "Next Release" milestone.
• Confirm the new version matches the expected next version.

Reviewers

After merging, create a GitHub Release to tag the new version.

Requirements

• 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 78.20%. Comparing base (73dde37) to head (592a560).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #663      +/-   ##
==========================================
+ Coverage   78.18%   78.20%   +0.02%     
==========================================
  Files         239      239              
  Lines       18136    18136              
==========================================
+ Hits        14179    14183       +4     
+ Misses       3957     3953       -4     

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