[Framework] Fixed error in register_raw when there's no relevant mappings for a specific kind

[omby8888]

Description

What - Fixed error in register_raw when there's no relevant mappings for a specific kind:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/tasks.py", line 267, in __step
    result = coro.send(None)
             ^^^^^^^^^^^^^^^
  File "/Users/omribarouch/Desktop/ocean/integrations/gitlab/gitlab_integration/events/hooks/base.py", line 37, in on_hook
    await self._on_hook(body, project)
  File "/Users/omribarouch/Desktop/ocean/integrations/gitlab/gitlab_integration/events/hooks/merge_request.py", line 20, in _on_hook
    await ocean.register_raw(ObjectKind.MERGE_REQUEST, [merge_requests.asdict()])
  File "/Users/omribarouch/Desktop/ocean/port_ocean/context/ocean.py", line 105, in register_raw
    await self.integration.register_raw(kind, change, user_agent_type)
  File "/Users/omribarouch/Desktop/ocean/port_ocean/core/integrations/mixins/sync_raw.py", line 229, in register_raw
    registered_entities, entities_to_delete = zip_and_sum(
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ValueError: not enough values to unpack (expected 2, got 0)

This is happened to me when received merge request webhook from the gitlab integration, while the merge request mapping isn't created by default in the integration so the diffs object in port_ocean/core/integrations/mixins/sync_raw.py line 22 is empty

Type of change

Please leave one option from the following and delete the rest:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• New Integration (non-breaking change which adds a new integration)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Non-breaking change (fix of existing functionality that will not change current behavior)
• Documentation (added/updated documentation)

Screenshots

Include screenshots from your environment showing how the resources of the integration will look.

API Documentation

Provide links to the API documentation used for this integration.

[yairsimantov20]

🌊