Revert "feat: Custom fields in pre-chat form (#4135)" (#4182)

This reverts commit e730804b48.

app/javascript/widget/views/PreChatForm.vue

@@ -35,20 +35,13 @@ export default {
     },
   },
   methods: {
-    onSubmit({
-      fullName,
-      emailAddress,
-      message,
-      activeCampaignId,
-      phoneNumber,
-    }) {
+    onSubmit({ fullName, emailAddress, message, activeCampaignId }) {
       if (activeCampaignId) {
         bus.$emit('execute-campaign', activeCampaignId);
         this.$store.dispatch('contacts/update', {
           user: {
             email: emailAddress,
             name: fullName,
-            phone_number: phoneNumber,
           },
         });
       } else {
@@ -56,7 +49,6 @@ export default {
           fullName: fullName,
           emailAddress: emailAddress,
           message: message,
-          phoneNumber: phoneNumber,
         });
       }
     },