[BUG] Fix naming issue with mip and lp solver settings

[rgsl888prabhu]

Describe the bug
Thin client uses different naming compared to what is there in SDK, for example

Thin client	SDK
relative_mip_gap	mip_relative_gap
absolute_mip_gap	mip_absolute_gap

Steps/Code to reproduce bug

https://github.com/rapidsai/cuopt/blob/6499e52f8d48795b3373c14825d0f9b00cf84313/python/cuopt_self_hosted/cuopt_sh_client/thin_client_solver_settings.py#L207C13-L207C29

Expected behavior

Names should be same

[tmckayus]

Thanks @rgsl888prabhu, for now I have mapped this in the service so that the service API does not change.

[tmckayus]

I think the right thing to do here is add an alternate type to the Pydantic definitions and update the solver config structure. Then we can deprecate the old structure for a release or two, and only support the new one.

This remapping for backward compat was a late addition for 25.05 so we did not have time to update the openapi specs, etc, but I will see if I can do this formally via Pydantic.