Disable errorprone for platformtestprotos

Running errorprone on platformtestprotos took more than 45 minutes.
Disable it.

Bug: 197157393
Test: m RUN_ERROR_PRONE=1 javac-check
Change-Id: I4e62adfddb93489d83c7e41e4ecba75fdf654004
diff --git a/TestProtoLibraries.bp b/TestProtoLibraries.bp
index 513d45f..afc11bb 100644
--- a/TestProtoLibraries.bp
+++ b/TestProtoLibraries.bp
@@ -30,6 +30,6 @@
         type: "full",
     },
     errorprone: {
-        javacflags: ["-Xep:MissingOverride:OFF"], // b/72714520
+        enabled: false,
     },
 }