dkg: use slices.Contains to simplify code

[boqishan]

There is a new function added in the go1.21 standard library, which can make the code more concise and easy to read.

category: refactor
ticket: none

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.01%. Comparing base (3dadd81) to head (c4ac871).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
dkg/pedersen/reshare.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4201      +/-   ##
==========================================
+ Coverage   56.95%   57.01%   +0.05%     
==========================================
  Files         237      237              
  Lines       30601    30600       -1     
==========================================
+ Hits        17430    17447      +17     
+ Misses      10946    10925      -21     
- Partials     2225     2228       +3     

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