Introduce Backend fields
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### 1. Introduce Backend fields
* [x] Migrations
* [x] Add `consecutive_absence_count integer NOT NULL DEFAULT 0` to `analyzer_project_statuses`
* [x] Add `stale bigint NOT NULL DEFAULT 0` to `analyzer_namespace_statuses`
* [x] Add `:stale` to `Enums::Security.analyzer_statuses`
* [x] Add validation for greater than 0 for `:stale` in `AnalyzerNamespaceStatus` model
* [x] Update `ee/spec/factories/analyzer_namespace_statuses.rb` and failing specs
* [x] Expose stale status on `AnalyzerProjectStatusType`
task