Make the server send ODK v18 messages by default

The core message had been throttled to only generate v17 messages because we wanted to stabilize the format before making the code live.

PiperOrigin-RevId: 524309559
Merged from https://widevine-internal-review.googlesource.com/170311

Change-Id: I2d09c9f6c73f844fd509531e86285ad71d22690f

libwvdrmengine/oemcrypto/odk/test/odk_test.cpp

@@ -1119,7 +1119,7 @@ std::vector<VersionParameters> TestCases() {
       {0, 16, 5, 16, 5},
       {0, 17, 1, 17, 1},
       {0, 17, 2, 17, 2},
-      {0, 18, 2, 17, 2},  // Change to 18 when the default version is updated.
+      {0, 18, 2, 18, 2},  // Change to 19 when the default version is updated.
   };
   return test_cases;
 }