{LYN-4456} FileIO hooks for LegacyTestAdapter (#1635)

* Could not reproduce the unit test fail for the m_app->BeforeRun() failure,
* so I am adding file IO hooks to listen for errors during the fixture setup

Tests: failed to repro the issue
Signed-off-by: Jackson <23512001+jackalbe@users.noreply.github.com>

Code/Tools/AssetProcessor/native/tests/AssetProcessorTest.cpp

@@ -9,6 +9,7 @@
 
 #include <AzCore/Settings/SettingsRegistryMergeUtils.h>
 #include <AzCore/UserSettings/UserSettingsComponent.h>
+#include <AzCore/IO/FileIOEventBus.h>
 
 #include "BaseAssetProcessorTest.h"
 #include <native/utilities/BatchApplicationManager.h>
@@ -52,11 +53,13 @@ namespace AssetProcessor
     };
 
     class LegacyTestAdapter : public AssetProcessorTest,
-        public ::testing::WithParamInterface<std::string>
+        public ::testing::WithParamInterface<std::string>,
+        public AZ::IO::FileIOEventBus::Handler
     {
         void SetUp() override
         {
             AssetProcessorTest::SetUp();
+            AZ::IO::FileIOEventBus::Handler::BusConnect();
             
             static int numParams = 1;
             static char processName[] = {"AssetProcessorBatch"};
@@ -77,9 +80,15 @@ namespace AssetProcessor
         void TearDown() override
         {
             m_application.reset();
+            AZ::IO::FileIOEventBus::Handler::BusDisconnect();
             AssetProcessorTest::TearDown();
         }
 
+        void OnError([[maybe_unused]] const AZ::IO::SystemFile* file, const char* fileName, int errorCode) override
+        {
+            AZ_Error("LegacyTestAdapter", false, "File error detected with %s with code %d", fileName, errorCode);
+        }
+
         AZStd::unique_ptr<UnitTestAppManager> m_application;
 
     };