Make sure self-collision chcks entire skeleton, not just subrobot

[egordon]

Quick 1-line fix to Robot class.

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Before creating a pull request

• [ N/A ] Document new methods and classes
• [x] Format code with make format

Before merging a pull request

• [ N/A ] Set version target by selecting a milestone on the right side
• [ N/A ] Summarize this change in CHANGELOG.md
• [ N/A ] Add unit test(s) for this change

[codecov[bot]]

Codecov Report

Merging #624 (602548c) into master (b7d96e2) will decrease coverage by 0.00%. The diff coverage is 0.00%.

:exclamation: Current head 602548c differs from pull request most recent head 3a8fb01. Consider uploading reports for the commit 3a8fb01 to get more accurate results

@@            Coverage Diff             @@
##           master     #624      +/-   ##
==========================================
- Coverage   73.09%   73.08%   -0.01%     
==========================================
  Files         219      219              
  Lines        7864     7865       +1     
==========================================
  Hits         5748     5748              
- Misses       2116     2117       +1     

Impacted Files	Coverage Δ
src/robot/Robot.cpp	22.65% <0.00%> (-0.08%)	:arrow_down: