fix(plugin-ecommerce): variants validateOptions errors with SQLite when creating a new variant (#14054)

Fixes #13993

The PR makes it so we add the `not_equals` query constraint only if we
have `data.id` (which we don't have when creating a new variant).

Author: r1tsuu

packages/plugin-ecommerce/src/collections/variants/createVariantsCollection/hooks/validateOptions.ts

@@ -29,9 +29,11 @@ export const validateOptions: (props?: Props) => Validate =
       joins: {
         variants: {
           where: {
-            id: {
-              not_equals: data.id, // exclude the current variant from the search
-            },
+            ...(data.id && {
+              id: {
+                not_equals: data.id, // exclude the current variant from the search
+              },
+            }),
           },
         },
       },