First chance exceptions and missing logging when a service isn't given a service name

See https://github.com/dotnet/runtime/issues/62579#issuecomment-995320972

The default behavior for ServiceBase when a ServiceName isn't specified is to use an empty string.  Per https://docs.microsoft.com/en-us/windows/win32/api/winsvc/ns-winsvc-service_table_entrya 
> If the service is installed with the SERVICE_WIN32_OWN_PROCESS service type, this member is ignored, but cannot be NULL. This member can be an empty string ("").

The problem, however, is that later on we use `ServiceName` to construct a log: 
https://github.com/dotnet/runtime/blob/1a83f61a5a3368250e5bed2baf28aed0f9e59508/src/libraries/System.ServiceProcess.ServiceController/src/System/ServiceProcess/ServiceBase.cs#L238-L241

And EventLog will throw for an empty `Source`:
https://github.com/dotnet/runtime/blob/1a83f61a5a3368250e5bed2baf28aed0f9e59508/src/libraries/System.Diagnostics.EventLog/src/System/Diagnostics/EventLogInternal.cs#L1300-L1301

So in this common scenario all of these calls to WriteEventLog result in first chance exceptions, and nothing is logged:
https://github.com/dotnet/runtime/blob/1a83f61a5a3368250e5bed2baf28aed0f9e59508/src/libraries/System.ServiceProcess.ServiceController/src/System/ServiceProcess/ServiceBase.cs#L944-L958

In this scenario we can actually acquire the service name from SCM, it's returned in the ServiceMain callback https://docs.microsoft.com/en-us/windows/win32/api/winsvc/nc-winsvc-lpservice_main_functiona
> the first argument (lpServiceArgVectors[0]) is the name of the service

I have confirmed this to be the case.  So we can simply capture it here and set `ServiceName` rather than skipping it:
https://github.com/dotnet/runtime/blob/1a83f61a5a3368250e5bed2baf28aed0f9e59508/src/libraries/System.ServiceProcess.ServiceController/src/System/ServiceProcess/ServiceBase.cs#L866-L880

	private void WriteLogEntry(string message, EventLogEntryType type = EventLogEntryType.Information)
	{
	// EventLog failures shouldn't affect the service operation
	try
	{
	if (AutoLog)
	{
	EventLog.WriteEntry(message, type);
	}
	}
	catch
	{
	// Do nothing. Not having the event log is bad, but not starting the service as a result is worse.
	}
	}

	if (argCount > 0)
	{
	char argsAsPtr = (char)argPointer.ToPointer();

	//Lets read the arguments
	// the first arg is always the service name. We don't want to pass that in.
	args = new string[argCount - 1];

	for (int index = 0; index < args.Length; ++index)
	{
	// we increment the pointer first so we skip over the first argument.
	argsAsPtr++;
	args[index] = Marshal.PtrToStringUni((IntPtr)(*argsAsPtr))!;
	}
	}

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First chance exceptions and missing logging when a service isn't given a service name #62923

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	_eventLog = new EventLog("Application")
	{
	Source = ServiceName
	};

	if (Source.Length == 0)
	throw new ArgumentException(SR.NeedSourceToWrite);

First chance exceptions and missing logging when a service isn't given a service name #62923

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