fix(customers): clear filter text inputs on reset all

Reset full_name and email to empty strings instead of undefined so React
Hook Form clears the uncontrolled input DOM values, matching the companies
filter reset behavior.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/Tables/customers/useCustomerListPresenter.ts

@@ -160,8 +160,8 @@ const useCustomerListPresenter = () => {
       status: undefined,
       role: undefined,
       type: undefined,
-      full_name: undefined,
-      email: undefined,
+      full_name: "",
+      email: "",
       company_id: undefined,
     });
     setCompanySearch("");