fix(tests): add required id field to all DashboardWidget test objects

Update dashboard.test.ts to reflect the new required 'id' field
(SnakeCaseIdentifierSchema) added to DashboardWidgetSchema.

- Add meaningful snake_case id to every widget object in tests
- Update WidgetActionTypeSchema tests: 'script' and 'api' are now valid types
- Remove outdated assertion that 'script' should be rejected

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Copilot