Correct VersionNumberTest expectation

[ Merge of http://go/wvgerrit/209610 ]

Bug: 339917270
Test:  request_license_test (VersionNumberTest.VersionNumberChangeCanary)
Flag: Test only code
Change-Id: I58e36f8684d87e7894a15e1903637781c9f7df9c

libwvdrmengine/cdm/test/request_license_test.cpp

@@ -6191,7 +6191,7 @@ TEST(VersionNumberTest, VersionNumberChangeCanary) {
       android::base::GetProperty("ro.build.version.release", "");
   ASSERT_TRUE(release_number.size() > 0);
   // Reminder to change the Widevine CDM version number.
-  EXPECT_EQ("13", release_number)
+  EXPECT_EQ("15", release_number)
       << "The Android version number has changed. You need to update this test "
          "and also possibly update the Widevine version number in "
          "wv_android_constants.h";