settings page: Change cursor for date input to 'pointer'.

Currently, the cursor for the date input field in the settings page
is 'not-allowed' as it has the disabled attribute because we want
users to pick the date from the date picker. But this leads to
confusion whether the field is editable at all.

Change the cursor to 'pointer' to make it clear that the field has
a click action associated with it.

static/styles/settings.scss

@@ -1543,6 +1543,10 @@ body:not(.night-mode) #settings_page .custom_user_field .datepicker {
     opacity: 1;
 }
 
+#settings_page .custom_user_field_value.datepicker {
+    cursor: pointer;
+}
+
 #settings_page .custom_user_field .person_picker {
     min-width: 206px;
 }