⬆️ Update googletest and Boost Multiprecision dependencies

[burgholzer]

Description

This pull request updates the following dependencies to their latest stable versions:

• googletest: from 1.14.0 to 1.16.0
• Boost Multiprecision: from 1_84_0 to 1_86_0

These updates bring in the latest fixes, performance improvements, and compatibility enhancements. No new dependencies are introduced.

Checklist:

• The pull request only contains commits that are related to it.
• I have added appropriate tests and documentation.
• I have made sure that all CI jobs on GitHub pass.
• The pull request introduces no new warnings and follows the project's style guidelines.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.3%. Comparing base (fc6bb4b) to head (eb94890).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #840   +/-   ##
=====================================
  Coverage   92.3%   92.3%           
=====================================
  Files        127     127           
  Lines      13556   13556           
  Branches    2086    2086           
=====================================
+ Hits       12520   12521    +1     
+ Misses      1036    1035    -1     

Flag	Coverage Δ
cpp	92.1% <ø> (+<0.1%)	⬆️
python	99.7% <ø> (ø)

see 1 file with indirect coverage changes