fix the display issue and run error in sample notebook

[ruixinxu]

1. update following files to make sure display() results show up in the sample center

• Notebooks/PySpark/08 Creating an unmanaged Spark Table.ipynb
• Notebooks/Scala/08 Creating an unmanaged Spark Table.ipynb
• Notebooks/Scala/09 Creating a managed Spark Table.ipynb
• Notebooks/SparkSQL/08 Creating an unmanaged Spark Table.ipynb
• Notebooks/SparkSQL/09 Creating a managed Spark Table.ipynb

2. Add display() for spark.net

   • Notebooks/Spark.NET C#/08 Creating an unmanaged Spark Table.ipynb
   • Notebooks/Spark.NET C#/09 Creating a managed Spark Table.ipynb

3. fix the run failure in following example according to bug https://msdata.visualstudio.com/A365/_queries/edit/882807/?triage=true

   • Notebooks/Scala/Updates and GDPR using Delta Lake - Scala.ipynb