Made clearing the log file optional and renamed the function

Signed-off-by: Guthrie Adams <guthadam@amazon.com>

Code/Framework/AzToolsFramework/AzToolsFramework/Logger/TraceLogger.cpp

@@ -50,7 +50,7 @@ namespace AzToolsFramework
         return false;
     }
 
-    void TraceLogger::PrepareLogFile(const AZStd::string& logFileName)
+    void TraceLogger::OpenLogFile(const AZStd::string& logFileName, bool clearLogFile)
     {
         using namespace AzFramework;
 
@@ -73,7 +73,7 @@ namespace AzToolsFramework
         AZStd::string logPath;
         StringFunc::Path::Join(logDirectory.c_str(), logFileName.c_str(), logPath);
 
-        m_logFile.reset(aznew LogFile(logPath.c_str(), true));
+        m_logFile.reset(aznew LogFile(logPath.c_str(), clearLogFile));
         if (m_logFile)
         {
             m_logFile->SetMachineReadable(false);

Code/Framework/AzToolsFramework/AzToolsFramework/Logger/TraceLogger.h

@@ -23,7 +23,7 @@ namespace AzToolsFramework
         ~TraceLogger();
 
         //! Open log file and dump log sink into it
-        void PrepareLogFile(const AZStd::string& logFileName);
+        void OpenLogFile(const AZStd::string& logFileName, bool clearLogFile);
 
         //! Add filter to ignore messages for windows with matching names
         void AddWindowFilter(const AZStd::string& filter);

Gems/Atom/Tools/AtomToolsFramework/Code/Source/Application/AtomToolsApplication.cpp

@@ -175,7 +175,8 @@ namespace AtomToolsFramework
 
         Base::StartCommon(systemEntity);
 
-        m_traceLogger.PrepareLogFile(GetBuildTargetName() + ".log");
+        const bool clearLogFile = GetSettingOrDefault("/O3DE/AtomToolsFramework/Application/ClearLogOnStart", false);
+        m_traceLogger.OpenLogFile(GetBuildTargetName() + ".log", clearLogFile);
 
         AzToolsFramework::AssetDatabase::AssetDatabaseRequestsBus::Handler::BusConnect();
         AzToolsFramework::AssetBrowser::AssetDatabaseLocationNotificationBus::Broadcast(