Fix installation of keystore2_key_contexts files

system_ext, product, and vendor keystore2_key_contexts are not installed
correctly, due to missing REQUIRED dependencies and typo.

Bug: 338684892
Test: build and check each partition
Change-Id: Ic18bf05609d27c322375baf6b72f5e2c75c1bfa0
diff --git a/contexts/Android.bp b/contexts/Android.bp
index 464c772..ca3cf57 100644
--- a/contexts/Android.bp
+++ b/contexts/Android.bp
@@ -315,7 +315,7 @@
 }
 
 keystore2_key_contexts {
-    name: "system_keystore2_key_contexts",
+    name: "system_ext_keystore2_key_contexts",
     defaults: ["contexts_flags_defaults"],
     srcs: [":keystore2_key_contexts_files{.system_ext_private}"],
     system_ext_specific: true,