fix: Tax region + rates clean up (#9279)

What
- Require `code` on Tax Rates
- Update dashboard to account for non-nullable code on Tax Rates

- Include `automatic_taxes` in API Route response

Closes CC-524 CC-525

packages/modules/tax/src/models/tax-rate.ts

@@ -61,8 +61,8 @@ export default class TaxRate {
   rate: number | null = null
 
   @Searchable()
-  @Property({ columnType: "text", nullable: true })
-  code: string | null = null
+  @Property({ columnType: "text" })
+  code: string
 
   @Searchable()
   @Property({ columnType: "text" })