[ITensors] Pass eigen_perturbation properly to factorize_eigen

[mtfishman]

Fixes #1239.

Also improves keyword argument style in dmrg.

[mtfishman]

[test ITensors mps]

[github-actions]

Run ITensors mps tests from comment trigger: failed ❌
https://github.com/ITensor/ITensors.jl/actions/runs/6777505021

[github-actions]

Run ITensors mps tests from comment trigger: failed ❌
https://github.com/ITensor/ITensors.jl/actions/runs/6777505021

[codecov-commenter]

Codecov Report

Attention: 12 lines in your changes are missing coverage. Please review.

Comparison is base (2dd057b) 54.56% compared to head (00d0075) 54.58%.

❗ Current head 00d0075 differs from pull request most recent head 4fa2c6b. Consider uploading reports for the commit 4fa2c6b to get more accurate results

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1240      +/-   ##
==========================================
+ Coverage   54.56%   54.58%   +0.02%     
==========================================
  Files          88       88              
  Lines        8392     8376      -16     
==========================================
- Hits         4579     4572       -7     
+ Misses       3813     3804       -9     

Files	Coverage Δ
src/tensor_operations/matrix_decomposition.jl	89.93% <100.00%> (+1.00%)	⬆️
src/mps/dmrg.jl	0.00% <0.00%> (ø)

... and 8 files with indirect coverage changes

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[mtfishman]

[test ITensors mps]

[github-actions]

Run ITensors mps tests from comment trigger: failed ❌
https://github.com/ITensor/ITensors.jl/actions/runs/6778552062

[github-actions]

Run ITensors mps tests from comment trigger: failed ❌
https://github.com/ITensor/ITensors.jl/actions/runs/6778552062

[mtfishman]

[test ITensors mps]

[github-actions]

Run ITensors mps tests from comment trigger: failed ❌
https://github.com/ITensor/ITensors.jl/actions/runs/6778738521

[github-actions]

Run ITensors mps tests from comment trigger: failed ❌
https://github.com/ITensor/ITensors.jl/actions/runs/6778738521

[mtfishman]

[test ITensors mps]

[github-actions]

Run ITensors mps tests from comment trigger: succeeded ✅
https://github.com/ITensor/ITensors.jl/actions/runs/6785232602

[github-actions]

Run ITensors mps tests from comment trigger: succeeded ✅
https://github.com/ITensor/ITensors.jl/actions/runs/6785232602