Mobile: Update appointments to use VAOS for local time (#12933)

* WIP

* Maintain mobile fallback in the event vaos does not return a local time

modules/mobile/app/models/mobile/v0/adapters/vaos_v2_appointment.rb

@@ -92,7 +92,7 @@ def build_appointment_model
             location:,
             minutes_duration: minutes_duration(appointment[:minutes_duration]),
             phone_only: appointment[:kind] == PHONE_KIND,
-            start_date_local: start_date_utc&.in_time_zone(timezone),
+            start_date_local:,
             start_date_utc:,
             status:,
             status_detail: cancellation_reason(appointment[:cancelation_reason]),
@@ -230,6 +230,14 @@ def start_date_utc
           end
         end
 
+        def start_date_local
+          @start_date_local ||= begin
+            DateTime.parse(appointment[:local_start_time])
+          rescue
+            start_date_utc&.in_time_zone(timezone)
+          end
+        end
+
         def appointment_type
           case appointment[:kind]
           when 'phone', 'clinic'