Fix missing in.current_cell parameter entry.

[MFraters]

in.current_cell was never filled in the material_model_inputs struct, but when a cpo particle has Minerals = Olivine: Karato 2008 it is used, leading to the crasch in #6237.

This fixes #6237 for me. @danieldouglas92 could you give this a go?

[danieldouglas92]

This does fix the test case that I posted in Issue #6237 on my local machine! Thanks @MFraters

[MFraters]

Oke, it looks like this is ready for review. @danieldouglas92 will add a test based on his test setup.

[danieldouglas92]

I created a test which imposes a differential stress of 350 MPa, and a water content which varies from 0 to 1000 along the x-dimension of the model. This means that the stress/water space follows the black line shown on the figure below. The test shows that we end up with the correct fabrics, going from an A-fabric (mineral id = 1) at x=-0.5 to a B-fabric (mineral id = 2) at x=0.5, with a transition from E-fabric (mineral id = 5) to C-fabric (mineral id = 3) in between.

[gassmoeller]

The change looks good, can you rebase to fix the documentation tester and update the test results?

Also add a changelog entry if this was introduced before 3.0 (which I think it was), just so we know it is already fixed if the issue comes up for anyone.

[MFraters]

I have rebased the pull request and fixed the test results and made a changelog entry. So ready for another review.

[gassmoeller]

Yes, good to go if you address my comments and squash your commits.

[gassmoeller]

Suggested change

	Fixed: Adds current cell to material model intpust
	Fixed: Add the current cell to the material model inputs

[gassmoeller]

Suggested change

	2008 mineral type. Also added a test to test this feature.
	2008 mineral type. Also added a test for this feature.