`run_custom_build` does not create source/compilation units

There doesn't seem to be a way to use custom builds with slither because none of the artifacts from the build command are used to create source/compilation units
https://github.com/crytic/crytic-compile/blob/10104f33f593ab82ba5780a5fe8dd26385acd1c1/crytic_compile/crytic_compile.py#L562

See https://github.com/crytic/slither/discussions/1866

Start at crytic_compile/crytic_compile.py around line 562 and trace the run_custom_build path to understand how its build artifacts are handled. Use the linked Slither discussion as the reproduction context; done means artifacts from a custom build create the source and compilation units needed by Slither.

Written by the indexing model from the issue text.