Remove the unused clearcut_extensions.proto file.

Bug: b/320511787
Change-Id: I3450abfed1a5f2a92d6cc4eb5ff311ca819587a6
Reviewed-on: https://fuchsia-review.googlesource.com/c/cobalt/+/974955
Reviewed-by: Alexandre Zani <azani@google.com>
Commit-Queue: Cameron Dale <camrdale@google.com>
diff --git a/src/pb/clearcut_extensions.proto b/src/pb/clearcut_extensions.proto
deleted file mode 100644
index 776a78b..0000000
--- a/src/pb/clearcut_extensions.proto
+++ /dev/null
@@ -1,11 +0,0 @@
-syntax = "proto2";
-
-package cobalt.clearcut_extensions;
-
-import "src/pb/encrypted_message.proto";
-
-message LogEventExtension {
-  oneof value {
-    cobalt.EncryptedMessage cobalt_encrypted_envelope = 705;
-  }
-}