Remove migration views (#3664)

* Remove migration views

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 CCs since they still use the views.

* remove if_exists=true for create_view, this option is not valid for create_view

Author: kathap

db/migrations/20240229113008_drop_annotations_and_labels_migration_views.rb

@@ -0,0 +1,48 @@
+Sequel.migration do
+  table_base_names = %w[
+    app
+    build
+    buildpack
+    deployment
+    domain
+    droplet
+    isolation_segment
+    organization
+    package
+    process
+    revision
+    route_binding
+    route
+    service_binding
+    service_broker
+    service_broker_update_request
+    service_instance
+    service_key
+    service_offering
+    service_plan
+    space
+    stack
+    task
+    user
+  ].freeze
+  annotation_tables = table_base_names.map { |tbn| "#{tbn}_annotations" }.freeze
+  label_tables = table_base_names.map { |tbn| "#{tbn}_labels" }.freeze
+
+  no_transaction # Disable automatic transactions
+
+  up do
+    (annotation_tables + label_tables).each do |table|
+      transaction do
+        drop_view(:"#{table}_migration_view", if_exists: true)
+      end
+    end
+  end
+
+  down do
+    (annotation_tables + label_tables).each do |table|
+      transaction do
+        create_view(:"#{table}_migration_view", self[table.to_sym].select { [id, guid, created_at, updated_at, resource_guid, key_prefix, key_name, value] })
+      end
+    end
+  end
+end