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 78.19%. Comparing base (93bd2a7) to head (03f1c0b).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #663   +/-   ##
=======================================
  Coverage   78.19%   78.19%           
=======================================
  Files         239      239           
  Lines       18132    18132           
=======================================
+ Hits        14178    14179    +1     
+ Misses       3954     3953    -1     

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