Merge pull request #1164 from Safelite/feature/CSR-1450

CSR-1450 | Nullcheck to fix defect

src/store/index.js

@@ -343,7 +343,7 @@ export const mutations = {
 
         //early bird fee used on schedule page also needs reset when schedule is reset
         const supportingItems = state.order.lineItems.supportingItems;
-        const removeEarlyBirdIndex = supportingItems.findIndex(
+        const removeEarlyBirdIndex = supportingItems?.findIndex(
             (item) => item.partType == PREMIUM_FEE_PART_TYPE
         );