refactor: move duplicate account import warnings to notification constants

- Add NOTIFY_DUPLICATE_ACCOUNT_IMPORT constant for import warnings
- Add NOTIFY_DUPLICATE_DERIVED_ACCOUNT constant for derived account warnings
- Update ImportAccountView.vue to use notification constants
- Update ImportDerivedAccountView.vue to use notification constants
- Update test file to use notification constants for assertions

Centralizes notification messages for better maintainability and consistency
with the existing notification system.

Files modified:
- src/constants/notifications.ts: Add new notification constants
- src/views/ImportAccountView.vue: Replace hardcoded messages with constants
- src/views/ImportDerivedAccountView.vue: Replace hardcoded messages with constants
- test-playwright/duplicate-import-test.spec.ts: Update test assertions

src/views/ImportAccountView.vue

@@ -95,6 +95,7 @@ import {
 import { retrieveAccountCount, importFromMnemonic } from "../libs/util";
 import { PlatformServiceMixin } from "@/utils/PlatformServiceMixin";
 import { createNotifyHelpers, TIMEOUTS } from "@/utils/notify";
+import { NOTIFY_DUPLICATE_ACCOUNT_IMPORT } from "@/constants/notifications";
 
 /**
  * Import Account View Component
@@ -206,7 +207,7 @@ export default class ImportAccountView extends Vue {
       const isDuplicate = await this.checkForDuplicateAccount();
       if (isDuplicate) {
         this.notify.warning(
-          "This account has already been imported. Please use a different seed phrase or check your existing accounts.",
+          NOTIFY_DUPLICATE_ACCOUNT_IMPORT.message,
           TIMEOUTS.LONG,
         );
         return;
@@ -246,7 +247,7 @@ export default class ImportAccountView extends Vue {
         errorMessage.includes("Cannot import duplicate account")
       ) {
         this.notify.warning(
-          "This account has already been imported. Please use a different seed phrase or check your existing accounts.",
+          NOTIFY_DUPLICATE_ACCOUNT_IMPORT.message,
           TIMEOUTS.LONG,
         );
         return;