Use system gtest and benchmark in Pixi tasks

[jslee02]

• Use system googletest and googlebenchmark within Pixi environments.
• Update googletest and googlebenchmark fetching to the latest versions
• Upgrade all other dependencies in Pixi environments by running pixi upgrade.
• Replace deprecated depends_on with depends-on in pixi.toml

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Before creating a pull request

• Document new methods and classes
• Format new code files using ClangFormat by running make format
• Build with -DDART_TREAT_WARNINGS_AS_ERRORS=ON and resolve all the compile warnings

Before merging a pull request

• Set version target by selecting a milestone on the right side
• Summarize this change in CHANGELOG.md
• Add unit test(s) for this change
• Add Python bindings for new methods and classes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.55%. Comparing base (c18c48a) to head (1da7345).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1905   +/-   ##
=======================================
  Coverage   61.54%   61.55%           
=======================================
  Files         490      490           
  Lines       46013    46013           
=======================================
+ Hits        28320    28322    +2     
+ Misses      17693    17691    -2     

see 1 file with indirect coverage changes