Update sysprop_library API txt

Internal props are no longer stored in the txt file.

Bug: 170693240
Test: m
Change-Id: I698b55d7b22afed71c94ee18fe76f409abc18baa

core/sysprop/api/com.android.sysprop.localization-current.txt

@@ -1,9 +0,0 @@
-props {
-  module: "android.sysprop.LocalizationProperties"
-  prop {
-    api_name: "locale_filter"
-    type: String
-    scope: Internal
-    prop_name: "ro.localization.locale_filter"
-  }
-}