Fix EPPlus VBA project removal for newer Excel files

[jochenwezel]

Summary

• Preserve the fallback workbook-level VBA cleanup when project removal throws NullReferenceException or EndOfStreamException.
• Apply the same isolated change to the Free/FixCalcs and Polyform engines.

Validation

• TestExcelOps, CI_CD, .NET Framework 4.8: 233 passed, 0 failed, 15 skipped.
• TestExcelOps, CI_CD, .NET 8: 233 passed, 0 failed, 15 skipped.
• Tests executed from a short output path to avoid Windows path-length failures; copied assemblies verified against worktree build hashes.
• API documentation check and git diff --check passed.
• Existing dependency/build warnings remain outside this change.

Release

Release only after merge and a successful Build and Test run on main.

[github-actions]

Unit Test Statistics (ubuntu-latest) CompuMaster.MsExcelComInteropTest.dll

0 tests   0 ✅  0s ⏱️
0 suites  0 💤
0 files    0 ❌

Results for commit db8f0cb.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (macos-latest) CompuMaster.MsExcelComInteropTest.dll

0 tests   0 ✅  0s ⏱️
0 suites  0 💤
0 files    0 ❌

Results for commit db8f0cb.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (ubuntu-latest) CompuMaster.Excel.Test.dll

0 tests   0 ✅  0s ⏱️
0 suites  0 💤
0 files    0 ❌

Results for commit db8f0cb.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (windows-latest) CompuMaster.MsExcelComInteropTest.dll

2 tests  ±0   2 ✅ ±0   0s ⏱️ ±0s
1 suites ±0   0 💤 ±0 
1 files   ±0   0 ❌ ±0 

Results for commit db8f0cb. ± Comparison against base commit c453b8d.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (ubuntu-latest) CompuMaster.Excel.TestFreeSpireXls.dll

0 tests   0 ✅  0s ⏱️
0 suites  0 💤
0 files    0 ❌

Results for commit db8f0cb.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (macos-latest) CompuMaster.Excel.Test.dll

0 tests   0 ✅  0s ⏱️
0 suites  0 💤
0 files    0 ❌

Results for commit db8f0cb.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (ubuntu-latest) CompuMaster.Excel.TestSpireXls.dll

0 tests   0 ✅  0s ⏱️
0 suites  0 💤
0 files    0 ❌

Results for commit db8f0cb.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (windows-latest) CompuMaster.Excel.Test.dll

259 tests  ±0   259 ✅ ±0   40s ⏱️ +3s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit db8f0cb. ± Comparison against base commit c453b8d.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (macos-latest) CompuMaster.Excel.TestFreeSpireXls.dll

0 tests   0 ✅  0s ⏱️
0 suites  0 💤
0 files    0 ❌

Results for commit db8f0cb.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (macos-latest) CompuMaster.Excel.TestSpireXls.dll

0 tests   0 ✅  0s ⏱️
0 suites  0 💤
0 files    0 ❌

Results for commit db8f0cb.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (windows-latest) CompuMaster.Excel.TestFreeSpireXls.dll

75 tests  ±0   75 ✅ ±0   20s ⏱️ -1s
 1 suites ±0    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit db8f0cb. ± Comparison against base commit c453b8d.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Statistics (windows-latest) CompuMaster.Excel.TestSpireXls.dll

77 tests  ±0   77 ✅ ±0   19s ⏱️ -1s
 1 suites ±0    0 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit db8f0cb. ± Comparison against base commit c453b8d.

♻️ This comment has been updated with latest results.