Enable mouse middle and right buttons for ImGui

[jslee02]

---

Before creating a pull request

• Document new methods and classes
• Format new code files using clang-format

Before merging a pull request

• Set version target by selecting a milestone on the right side
• Summarize this change in CHANGELOG.md

[codecov]

Codecov Report

Merging #1500 into master will decrease coverage by 0.03%.
The diff coverage is 11.11%.

@@            Coverage Diff             @@
##           master    #1500      +/-   ##
==========================================
- Coverage   58.20%   58.17%   -0.04%     
==========================================
  Files         412      414       +2     
  Lines       29913    30008      +95     
==========================================
+ Hits        17412    17456      +44     
- Misses      12501    12552      +51     

Impacted Files	Coverage Δ
dart/collision/CollisionResult.cpp	70.73% <0.00%> (ø)
dart/constraint/BoxedLcpConstraintSolver.cpp	53.00% <0.00%> (ø)
dart/dynamics/PyramidShape.hpp	0.00% <0.00%> (ø)
dart/dynamics/Skeleton.hpp	83.33% <ø> (ø)
dart/collision/fcl/FCLCollisionDetector.cpp	85.62% <2.85%> (-4.01%)	⬇️
dart/dynamics/PyramidShape.cpp	6.25% <6.25%> (ø)
dart/utils/SkelParser.cpp	66.66% <14.28%> (-0.39%)	⬇️
dart/dynamics/Skeleton.cpp	66.22% <100.00%> (+0.05%)	⬆️
dart/dynamics/detail/GenericJoint.hpp	75.47% <100.00%> (+0.03%)	⬆️
... and 6 more