update mcp descriptions

[mirror58229]

Ⅰ. Describe what this PR did

1. Fix bravesearch
2. Add librechat and wolframalpha

Ⅱ. Does this pull request fix one issue?

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.66%. Comparing base (ef31e09) to head (4c5ca36).
Report is 460 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2105      +/-   ##
==========================================
+ Coverage   35.91%   43.66%   +7.75%     
==========================================
  Files          69       79      +10     
  Lines       11576    12753    +1177     
==========================================
+ Hits         4157     5569    +1412     
+ Misses       7104     6836     -268     
- Partials      315      348      +33     

see 75 files with indirect coverage changes

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[johnlanni]

LGTM