Allow us to set CategoryName when using the logging bridge API

[AB027PS]

Feature Request

Is your feature request related to a problem?

If I create a logger with the OtlpExporter using the bridge API and then emit a log, an exception will be thrown at line 50 here

opentelemetry-dotnet/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/OtlpLogRecordTransformer.cs

Lines 45 to 55 in 0b9cf42

	foreach (var logRecord in logRecordBatch)
	{
	var otlpLogRecord = this.ToOtlpLog(logRecord);
	if (otlpLogRecord != null)
	{
	if (!logsByCategory.TryGetValue(logRecord.CategoryName, out var scopeLogs))
	{
	scopeLogs = this.GetLogListFromPool(logRecord.CategoryName);
	logsByCategory.Add(logRecord.CategoryName, scopeLogs);
	resourceLogs.ScopeLogs.Add(scopeLogs);
	}

because logRecord.CategoryName will be null. A possible workaround is to create a processor which will set CategoryName to a non-null value on each LogRecord separately, but that only prevents the exceptions and doesn't address the feature request.

Describe the solution you'd like:

Add a CategoryName property to the LogRecordData struct.

[CodeBlanch]

@AB027PS Thanks for this bug report! I commented on the PR but I think a better change would be something like this inside OtlpExporter:

         var scopeName = logRecord.CategoryName ?? logRecord.Logger?.Name ?? DefaultScopeName;
         if (!logsByCategory.TryGetValue(scopeName, out var scopeLogs)) 
         { 
             scopeLogs = this.GetLogListFromPool(scopeName); 
             logsByCategory.Add(scopeName, scopeLogs); 
             resourceLogs.ScopeLogs.Add(scopeLogs); 
         }