Remove migration views

[kathap]

After merging #3394 and #3393 we can remove the views we introduced for annotations and labels tables.

This is a breaking change, migrating from a CF-Deployment version before PR 3394 to a version that removes the view will cause a downtime on the old CloudControllers since they still use the views.

In this database migration the annotations and labels migrations views will be dropped. They were introduced to in #3394 to help implementing the uniqueness of labels and annotations, they have no other use in the code. Now that #3394 and #3393 are through, the views are not needed anymore and can be deleted.

• Links to any other associated PRs #3394 and #3393

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• [x] I have made this pull request to the main branch

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