Hotfix some direct solve ambiguities

[termi-official]

Hotfix as proposed in https://github.com/JuliaArrays/BlockArrays.jl/issues/319

[codecov[bot]]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (d44e944) 87.47% compared to head (300ceaf) 0.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #181       +/-   ##
==========================================
- Coverage   87.47%   0.00%   -87.48%     
==========================================
  Files          11      11               
  Lines        1812    1712      -100     
==========================================
- Hits         1585       0     -1585     
- Misses        227    1712     +1485     

Files	Coverage Δ
src/ldiv.jl	0.00% <0.00%> (-90.56%)	:arrow_down:
ext/ArrayLayoutsSparseArraysExt.jl	0.00% <0.00%> (-100.00%)	:arrow_down:

... and 9 files with indirect coverage changes

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[termi-official]

I am still lost why only the WY form has issues, but this PR should fix it. Plus it fixes ambiguities with some sparse direct solve dispatches.