set an explicit SDK version for CTS preconditions

The apk does not really depend on the "current"
version of SDK

Bug: 78936796
Test: make -j CtsPreconditions
Change-Id: I7977a7984abc3f537c5a1aa0780daba74d683186
(cherry picked from commit b373d99be446a0fcebbff0e01e7e5bf681adf8b8)
diff --git a/tools/cts-preconditions/Android.mk b/tools/cts-preconditions/Android.mk
index 5f00c36..9c8cbf2 100644
--- a/tools/cts-preconditions/Android.mk
+++ b/tools/cts-preconditions/Android.mk
@@ -38,6 +38,6 @@
 
 LOCAL_PACKAGE_NAME := CtsPreconditions
 
-LOCAL_SDK_VERSION := current
+LOCAL_SDK_VERSION := 26
 
 include $(BUILD_PACKAGE)