Add cutom data color property for mesh comparison

Add color data type comparison for meshes, adding it as
part of comparing meshes with geometry nodes applied.

Reviewed By: JacquesLucke

Differential Revision: https://developer.blender.org/D12192

source/blender/blenkernel/intern/mesh.c

@@ -638,6 +638,19 @@ static int customdata_compare(
           }
           break;
         }
+        case CD_PROP_COLOR: {
+          const MPropCol *l1_data = l1->data;
+          const MPropCol *l2_data = l2->data;
+
+          for (int i = 0; i < total_length; i++) {
+            for (int j = 0; j < 4; j++) {
+              if (fabsf(l1_data[i].color[j] - l2_data[i].color[j]) > thresh) {
+                return MESHCMP_ATTRIBUTE_VALUE_MISMATCH;
+              }
+            }
+          }
+          break;
+        }
         default: {
           break;
         }