Remove SetAerosolScope function

[boulderdaze]

Since introducing ExternalModel abstraction, the following functions have no usage.

Deletes SetAerosolScope(), JoinStrings(...)

[Copilot]

Pull request overview

This PR removes the ChemicalReactionBuilder::SetAerosolScope API (and associated scoping logic) along with its unit tests, based on it having no remaining usage since the ExternalModel abstraction was introduced.

Changes:

• Removed SetAerosolScope from ChemicalReactionBuilder and deleted all related scoping/state-tracking logic.
• Deleted the process_configuration unit test file that validated aerosol scoping behavior and removed the test target from CMake.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
include/micm/process/chemical_reaction_builder.hpp	Removes the SetAerosolScope public API and related internal scoping logic.
test/unit/process/test_process_configuration.cpp	Deletes the unit tests that covered the removed aerosol scoping behavior.
test/unit/process/CMakeLists.txt	Removes the process_configuration test target so the deleted test file is no longer built.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

You can also share your feedback on Copilot code review. Take the survey.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.04%. Comparing base (636a86f) to head (a5a907a).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #947      +/-   ##
==========================================
- Coverage   94.28%   94.04%   -0.24%     
==========================================
  Files          69       68       -1     
  Lines        3833     3797      -36     
==========================================
- Hits         3614     3571      -43     
- Misses        219      226       +7     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.