Fix invalid key session id

Merge of https://widevine-internal-review.googlesource.com/c/cdm/+/169871

The default invalid entitled key session id was 0, which in fact could
be a valid value depending on how the key session id is allocated by the
implementation. This can be a possible cause of L3 entitled key session
failure since L3 can recycle a regular oemcrypto session id 0 and
re-assign it to an entitled key session later.

Bug: 264688931
Test: Run GTS media tests

Change-Id: Iae79d08378d61be8a3402f606992765f24298508

libwvdrmengine/cdm/core/src/entitlement_key_session.cpp

@@ -10,7 +10,7 @@
 
 namespace wvcdm {
 namespace {
-constexpr int kInvalidKeySessionId = 0;
+constexpr uint32_t kInvalidKeySessionId = 0xFFFFFFFF;
 }  // namespace
 
 EntitlementKeySession::EntitlementKeySession(