[projmgr] add-path: filter out duplicates and tolerate absolute paths (#1142)

[spcaipers-arm]

Address #1938
Update test cases

[github-actions]

Test Results

    3 files     18 suites   9m 40s ⏱️
  381 tests   381 ✅ 0 💤 0 ❌
1 143 runs  1 143 ✅ 0 💤 0 ❌

Results for commit 3a32005.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

Attention: Patch coverage is 72.41379% with 8 lines in your changes missing coverage. Please review.

Project coverage is 65.47%. Comparing base (b5277bf) to head (3a32005).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
tools/projmgr/test/src/ProjMgrUnitTests.cpp	53.84%	3 Missing and 3 partials ⚠️
tools/projmgr/src/ProjMgrCbuildBase.cpp	85.71%	0 Missing and 1 partial ⚠️
tools/projmgr/src/ProjMgrWorker.cpp	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1970      +/-   ##
==========================================
- Coverage   65.48%   65.47%   -0.01%     
==========================================
  Files         173      173              
  Lines       35151    35160       +9     
  Branches    20405    20414       +9     
==========================================
+ Hits        23017    23020       +3     
- Misses       7905     7908       +3     
- Partials     4229     4232       +3     

Flag	Coverage Δ
projmgr-cov	81.81% <72.41%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
tools/projmgr/include/ProjMgrCbuildBase.h	100.00% <ø> (ø)
tools/projmgr/src/ProjMgrCbuild.cpp	93.38% <100.00%> (-0.02%)	⬇️
tools/projmgr/src/ProjMgrYamlParser.cpp	82.11% <ø> (-0.03%)	⬇️
tools/projmgr/src/ProjMgrCbuildBase.cpp	88.88% <85.71%> (-2.03%)	⬇️
tools/projmgr/src/ProjMgrWorker.cpp	88.13% <66.66%> (-0.03%)	⬇️
tools/projmgr/test/src/ProjMgrUnitTests.cpp	80.77% <53.84%> (-0.08%)	⬇️