chore: fix comment in fetch-dashboard-assets.sh

[tisonkun]

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What's changed and what's your intention?

TRIVIAL AS IS

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR does not require documentation updates.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.36%. Comparing base (6377982) to head (ba55ead).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3546      +/-   ##
==========================================
- Coverage   85.36%   85.36%   -0.01%     
==========================================
  Files         910      910              
  Lines      152030   152030              
==========================================
- Hits       129780   129775       -5     
- Misses      22250    22255       +5     

[fengjiachun]

LGTM