fix: Periodic boundary conditions space mismatch for non-self-dual spaces

[lkdvos]

As brought up by @minalouschleith, non-self-dual spaces had a mistake in the fused spaces which led to space mismatches.

Also found a small mistake in the kitaev model test version that should now be fixed.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Files with missing lines	Coverage Δ
src/algorithms/toolbox.jl	97.86% <100.00%> (ø)

... and 1 file with indirect coverage changes

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