Fix fermion cases in blocksparse SVD

[emstoudenmire]

Some previously working cases of the SVD for auto fermion stopped working due to changes in NDTensors/src/blocksparse/linearalgebra.jl. This PR changes those lines of code back to a correctly working version and restores the corresponding tests which were marked as broken.

With this PR, all four "matrix" cases of the SVD should again be working.

The other cases which are still marked as broken are also likely conceptually correct as long as one correctly conjugates certain mixed arrows with a parity tensor before determining whether U or V are unitary. So in a sense it is those last two tests which are broken, not the ITensor code. (This PR does not address those tests; just mentioning it for context.)

[mtfishman]

Thanks for catching that, that was my mistake.

[codecov-commenter]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (e571300) 85.39% compared to head (1ccc3a8) 67.34%.
Report is 2 commits behind head on main.

❗ Current head 1ccc3a8 differs from pull request most recent head 350370b. Consider uploading reports for the commit 350370b to get more accurate results

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Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1212       +/-   ##
===========================================
- Coverage   85.39%   67.34%   -18.05%     
===========================================
  Files          89       88        -1     
  Lines        8426     8388       -38     
===========================================
- Hits         7195     5649     -1546     
- Misses       1231     2739     +1508     

see 36 files with indirect coverage changes

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