refactor: convert PlatformmId to union (#18458)

lib/config/migration.spec.ts

lib/config/options/index.ts

lib/config/presets/local/index.ts

lib/config/types.ts

lib/constants/platform.spec.ts

lib/constants/platforms.ts

lib/modules/datasource/go/base.spec.ts

lib/modules/datasource/go/base.ts

lib/modules/manager/composer/artifacts.spec.ts

lib/modules/manager/composer/artifacts.ts

lib/modules/manager/gomod/artifacts.spec.ts

lib/modules/manager/gomod/artifacts.ts

lib/modules/manager/pre-commit/extract.ts

lib/modules/platform/azure/azure-got-wrapper.spec.ts

lib/modules/platform/azure/azure-got-wrapper.ts

lib/modules/platform/azure/index.ts

lib/modules/platform/bitbucket-server/index.ts

lib/modules/platform/bitbucket/index.ts

lib/modules/platform/gitea/index.spec.ts

lib/modules/platform/gitea/index.ts