Fix webhook creation/filtering with invalid org

[zhiltsov-max]

Motivation and context

Extracted from #5662

If a project webhook was created and an org was specified, the org from the request could be assigned to the webhook, while the project could be in another org or outside an org. Then, project events could not be delivered to the webhooks. This PR fixes this problem by ignoring the org specified in the request in favor of the org specified in the project.

• Fixed a possible bug in project/org handling for webhooks
• Added a test

How has this been tested?

Checklist

• I submit my changes into the develop branch
• I have added a description of my changes into the CHANGELOG file
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (see GitHub docs)
• I have increased versions of npm packages if it is necessary
  (cvat-canvas,
  cvat-core,
  cvat-data and
  cvat-ui)

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.

[sizov-kirill]

LGTM