Fix 1 ClangTidyBuild finding:

[ Merge of http://go/wvgerrit/145289 ]

* missing #include <string> for 'std::string' For more info see go/clang_tidy/checks/google3-build-missing-std-includes

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Tested:
    Local presubmit tests passed.

Bug: 224375138
Test: GtsTestCases on sunfish

PiperOrigin-RevId: 426761099
Merged from https://widevine-internal-review.googlesource.com/145250

Change-Id: I5a66b6eccc2b08ee11f92f90ce3b725f24c8d33c

libwvdrmengine/oemcrypto/odk/test/fuzzing/odk_fuzz_helper.cpp

@@ -3,6 +3,8 @@
 // License Agreement.
 #include "fuzzing/odk_fuzz_helper.h"
 
+#include <string>
+
 #include "odk.h"
 
 namespace oemcrypto_core_message {