feat(medusa): migrate medusa unit tests / plugins integration tests to swc jest (#6820)

what:

- migrates medusa package to swc/jest
- migrates plugins integration tests to swc/jest
- parallelises a few of the heavy test packages
- fixes typeorm circular dependencies

**Unit Tests**

Before: 1 job => ~30 mins
After: 2 jobs => ~5 mins


<img width="260" alt="Screenshot 2024-03-25 at 15 11 49" src="https://github.com/medusajs/medusa/assets/5105988/e1df6985-5bd6-48d0-b87b-336d3c77d0cf">

**Plugins**

Before: 1 job => ~10 mins
After: 1 job => ~5 mins

<img width="254" alt="Screenshot 2024-03-25 at 15 26 03" src="https://github.com/medusajs/medusa/assets/5105988/c1cec0e2-a1c3-41d1-9372-46d114d804c6">



Co-authored-by: Adrien de Peretti <25098370+adrien2p@users.noreply.github.com>

packages/medusa/src/utils/feature-flag-decorators.ts

@@ -1,5 +1,7 @@
 import { Column, ColumnOptions, Entity, EntityOptions } from "typeorm"
 import { featureFlagRouter } from "../loaders/feature-flags"
+import { Equals, ValidateIf } from "class-validator"
+import { isDefined } from "@medusajs/utils"
 
 /**
  * If that file is required in a non node environment then the setImmediate timer does not exists.
@@ -15,7 +17,7 @@ try {
   console.warn(
     "[feature-flag-decorator.ts] setImmediate will use a mock, this happen when this file is required in a browser environment and should not impact you"
   )
-  setImmediate_ = (callback: () => void | Promise<void>) => callback()
+  setImmediate_ = async (callback: () => void | Promise<void>) => callback()
 }
 
 export function FeatureFlagColumn(
@@ -40,6 +42,10 @@ export function FeatureFlagDecorators(
   return function (target, propertyName) {
     setImmediate_((): any => {
       if (!featureFlagRouter.isFeatureEnabled(featureFlag)) {
+        ValidateIf((o) => isDefined(o[propertyName]))(target, propertyName)
+        Equals(undefined, {
+          message: `${propertyName as string} should not exist`,
+        })(target, propertyName)
         return
       }