chore: update proto definition to v1.4.0

[lalitb]

Changes

Just a routine update, even though it only brings doc updates for all the metrics. Major changes are in profiles proto file which doesn't affect us.

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.5%. Comparing base (ca6c67e) to head (7454bd6).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2315   +/-   ##
=====================================
  Coverage   79.5%   79.5%           
=====================================
  Files        123     123           
  Lines      21282   21282           
=====================================
+ Hits       16925   16927    +2     
+ Misses      4357    4355    -2     

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