Cleanup: Remove compile option for curves object

After becb1530b1 the new curves object type isn't hidden
behind an experimental flag anymore, and other areas depend on this,
so disabling curves at compile time doesn't make sense anymore.

source/blender/makesrna/intern/rna_main.c

@@ -96,9 +96,7 @@ RNA_MAIN_LISTBASE_FUNCS_DEF(collections)
 RNA_MAIN_LISTBASE_FUNCS_DEF(curves)
 RNA_MAIN_LISTBASE_FUNCS_DEF(fonts)
 RNA_MAIN_LISTBASE_FUNCS_DEF(gpencils)
-#  ifdef WITH_NEW_CURVES_TYPE
 RNA_MAIN_LISTBASE_FUNCS_DEF(hair_curves)
-#  endif
 RNA_MAIN_LISTBASE_FUNCS_DEF(images)
 RNA_MAIN_LISTBASE_FUNCS_DEF(lattices)
 RNA_MAIN_LISTBASE_FUNCS_DEF(libraries)
@@ -375,7 +373,6 @@ void RNA_def_main(BlenderRNA *brna)
        "Light Probes",
        "Light Probe data-blocks",
        RNA_def_main_lightprobes},
-#  ifdef WITH_NEW_CURVES_TYPE
       /**
        * \note The name `hair_curves` is chosen to be different than `curves`,
        * but they are generic curve data-blocks, not just for hair.
@@ -386,7 +383,6 @@ void RNA_def_main(BlenderRNA *brna)
        "Hair Curves",
        "Hair curve data-blocks",
        RNA_def_main_hair_curves},
-#  endif
       {"pointclouds",
        "PointCloud",
        "rna_Main_pointclouds_begin",