ci: revert Frontier staging/install cleanup in build.sh

[sbryngelson]

Summary

• Reverts the .github/workflows/common/build.sh hunk introduced in fix: extend CCE 19.0.0 -Oipa0 workaround to m_mpi_common.fpp #1409 (commit 141ff01) that added a Frontier/Frontier-AMD staging/install cleanup loop preserving silo|hdf5|lapack|fftw|hipfort dep dirs.
• Other changes from 141ff01 (CMakeLists.txt CCE 19.0.0 -Oipa0 workaround, toolchain/bootstrap/modules.sh) are kept.

Test plan

• Self-hosted Frontier / Frontier-AMD CI build runs cleanly without the wipe block.
• Phoenix CI path unchanged (still uses clean_build).

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.94%. Comparing base (87f299f) to head (2c1d50f).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1415   +/-   ##
=======================================
  Coverage   64.94%   64.94%           
=======================================
  Files          72       72           
  Lines       18861    18861           
  Branches     1570     1570           
=======================================
  Hits        12250    12250           
  Misses       5638     5638           
  Partials      973      973           

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