[MM-53428] Delete empty drafts on upsert (#24046)

* [MM-53428] Delete empty drafts on upsert

* Add migrations to fix existing drafts

* Fix CI

* Delete empty drafts entirely from the DB

* Fix lint

* Implement batch migration for deleting drafts

* Missing store layers

* Add updated mock

* Remove unnecessary test

* PR feedback

* Add check for cluster migration

* Fix MySQL

* Don't check for len<2

* Bit of PR feedback

* Use query builder for parameters

* PR feedback

* More PR feedback

* Merge'd

* unit test GetLastCreateAtAndUserIdValuesForEmptyDraftsMigration

* simplified builder interface

* fix DeleteEmptyDraftsByCreateAtAndUserId for MySQL

* rework as batch migration worker

* fix typo

* log ip address on version mismatches too

* simplify reset semantics

* remove trace log in favour of low spam

* document parameters for clarity

---------

Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Jesse Hallam <jesse.hallam@gmail.com>

server/channels/testlib/store.go

@@ -71,6 +71,7 @@ func GetMockStoreForSetupFunctions() *mocks.Store {
 	systemStore.On("GetByName", model.MigrationKeyAddPlayboosksManageRolesPermissions).Return(&model.System{Name: model.MigrationKeyAddPlayboosksManageRolesPermissions, Value: "true"}, nil)
 	systemStore.On("GetByName", model.MigrationKeyAddCustomUserGroupsPermissionRestore).Return(&model.System{Name: model.MigrationKeyAddCustomUserGroupsPermissionRestore, Value: "true"}, nil)
 	systemStore.On("GetByName", model.MigrationKeyAddReadChannelContentPermissions).Return(&model.System{Name: model.MigrationKeyAddReadChannelContentPermissions, Value: "true"}, nil)
+	systemStore.On("GetByName", model.MigrationKeyDeleteEmptyDrafts).Return(&model.System{Name: model.MigrationKeyDeleteEmptyDrafts, Value: "true"}, nil)
 	systemStore.On("GetByName", "CustomGroupAdminRoleCreationMigrationComplete").Return(&model.System{Name: model.MigrationKeyAddPlayboosksManageRolesPermissions, Value: "true"}, nil)
 	systemStore.On("GetByName", "products_boards").Return(&model.System{Name: "products_boards", Value: "true"}, nil)
 	systemStore.On("GetByName", "elasticsearch_fix_channel_index_migration").Return(&model.System{Name: "elasticsearch_fix_channel_index_migration", Value: "true"}, nil)