fix(telephony): Check if setup_phone method exists

We are just overriding Data control. 

This fails if other field type like "Small Text" has option set as "Phone"
diff --git a/erpnext/public/js/telephony.js b/erpnext/public/js/telephony.js
index 1c3e314..f4b0b18 100644
--- a/erpnext/public/js/telephony.js
+++ b/erpnext/public/js/telephony.js
@@ -8,7 +8,7 @@
 			Object.values(this.frm.fields_dict).forEach(function(field) {
 				if (field.df.read_only === 1 && field.df.options === 'Phone'
 					&& field.disp_area.style[0] != 'display' && !field.has_icon) {
-					field.setup_phone();
+					field.setup_phone && field.setup_phone();
 					field.has_icon = true;
 				}
 			});