chore: explicitly share error message used for logic

src/libs/util.ts

@@ -614,6 +614,8 @@ export const retrieveAllAccountsMetadata = async (): Promise<
   return result;
 };
 
+export const DUPLICATE_ACCOUNT_ERROR = "Cannot import duplicate account.";
+
 /**
  * Saves a new identity to both SQL and Dexie databases
  */
@@ -634,7 +636,7 @@ export async function saveNewIdentity(
 
     if (existingAccount?.values?.length) {
       throw new Error(
-        `Account with DID ${identity.did} already exists. Cannot import duplicate account.`,
+        `Account with DID ${identity.did} already exists. ${DUPLICATE_ACCOUNT_ERROR}`,
       );
     }