Revert "Mark libmetricslogger vendor_available."

This reverts commit 7f96d493705dd00757597018e6befa20b15bfc8b.

Reason for revert: depends on private liblog APIs
- log/log_event_list.h is not in the vndk

Change-Id: I448c2f1059bd6b225d8efff87eb3948e931de47a
diff --git a/libmetricslogger/Android.bp b/libmetricslogger/Android.bp
index 38859d1..26a041a 100644
--- a/libmetricslogger/Android.bp
+++ b/libmetricslogger/Android.bp
@@ -31,7 +31,6 @@
 // -----------------------------------------------------------------------------
 cc_library_shared {
     name: "libmetricslogger",
-    vendor_available: true,
     srcs: metricslogger_lib_src_files,
     defaults: ["metricslogger_defaults"],
 }