fix(dashboard): Make postalCode required to match Angular parity

Angular's select-address-dialog uses Validators.required on postalCode.
Updated the address form schema to match and added postalCode fill to
the e2e test.

Author: Ryrahul

packages/dashboard/e2e/tests/sales/orders.spec.ts

@@ -367,6 +367,7 @@ test.describe('Orders', () => {
         // Fill the inline address form
         await popover.getByLabel('Street Address').fill('99 Inline Road');
         await popover.getByLabel('City').fill('Inlineton');
+        await popover.getByLabel('Postal Code').fill('12345');
         // Country is a Select — open and pick the first available country
         await popover.getByRole('combobox').click();
         await page.getByRole('option').first().click();

packages/dashboard/src/lib/components/shared/customer-address-form.tsx

@@ -34,7 +34,7 @@ const addressFormSchema = z.object({
     streetLine2: z.string().optional(),
     city: z.string().min(1, { message: 'City is required' }),
     province: z.string().optional(),
-    postalCode: z.string().optional(),
+    postalCode: z.string().min(1, { message: 'Postal code is required' }),
     countryCode: z.string().min(1, { message: 'Country is required' }),
     phoneNumber: z.string().optional(),
     defaultShippingAddress: z.boolean(),