packages/apps/Car/Hvac: Set LOCAL_SDK_VERSION where possible.

This change sets LOCAL_SDK_VERSION for all packages where
this is possible without breaking the build, and
LOCAL_PRIVATE_PLATFORM_APIS := true otherwise.

Setting one of these two will be made required soon, and this
is a change in preparation for that. Not setting LOCAL_SDK_VERSION
makes the app implicitly depend on the bootclasspath, which is
often not required. This change effectively makes depending on
private apis opt-in rather than opt-out.

Test: make relevant packages
Bug: 73535841
Change-Id: I44ee40db66b82a5993f724d3c6b45c344e99745b
diff --git a/Android.mk b/Android.mk
index b53100b..5f91b42 100644
--- a/Android.mk
+++ b/Android.mk
@@ -25,6 +25,7 @@
 LOCAL_RESOURCE_DIR := $(LOCAL_PATH)/res
 
 LOCAL_PACKAGE_NAME := CarHvacApp
+LOCAL_PRIVATE_PLATFORM_APIS := true
 
 LOCAL_CERTIFICATE := platform