Fix ILU binding API mismatch

[2002kaihui]

Description

Fixes the ILU preconditioner binding to match the updated Ginkgo API.

The previous binding used the old gko::preconditioner::Ilu template interface with explicit lower and upper triangular solver types. The current Ginkgo API expects the template parameters in the form:

gko::preconditioner::Ilu<ValueType, ReverseApply, IndexType>

Type of change

• Bugfix (non-breaking change which fixes an issue)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• My changes generate no new warnings
• New and existing tests pass locally with my changes

[greole]

Thank you! LGTM! @yhmtsai We need to merge this into an internal branch first to run the CI. I'll give @2002kaihui access to this repo directly.