fix: Dashboard charts not loading (#16921)
fix: Dashboard charts not loading (#16921)

* fix: field undefined in chart widget

* fix: check if email signature was returned

arrays are truthy empty array wont fail first check but fail with "can't
read signature of undefined"

Co-authored-by: Suraj Shetty <c1fab1cf28e7dcca05cc07266aa459291053d3da@users.noreply.github.com>
StrellaGroup/frappe,yashodhank/frappe,yashodhank/frappe,yashodhank/frappe,StrellaGroup/frappe,frappe/frappe,frappe/frappe,StrellaGroup/frappe,yashodhank/frappe,frappe/frappe