Ticket: 43534

Description:
Split operation is able to return several outputs. For some cases can be one or several outputs which will not have any consumers. At this case we need to keep ports otherwise we will got incorrect IR. For that cases we connect Result nodes to disconnected ports with special attribute keep_output_port.
keep_output_port attribute to Result node mien that node will not be added to IR but keep output port with shape.

Code:

• Transformation tests
• Comments
• Code style (PEP8)
• Transformation generates reshape-able IR N/A (not reasonable to implement test. It is covered by e2e testing that is manually passing)
• Transformation preserves original framework node names

Validation:

• Unit tests
• Framework operation tests, no new operations were added: N/A
• Model Optimizer IR Reader check

Documentation:

• Supported frameworks operations list: N/A
• Guide on how to convert the public model: N/A
• User guide update: N/A