chore: sync changes from pg branch (#36556)

## Description
Added the changes from move to pg script from the postgres branch to
keep in sync.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

## Summary by CodeRabbit

- **New Features**
- Enhanced data transformation process for improved compatibility with
Postgres.
	- Introduced mapping for `_class` field to `type` field.

- **Bug Fixes**
- Improved handling of asynchronous operations during MongoDB client
instantiation.

- **Refactor**
- Clarified condition checks in data transformation logic for better
readability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

<!-- This is an auto-generated comment: Cypress test results  -->
> [!TIP]
> 🟢 🟢 🟢 All cypress tests have passed! 🎉 🎉 🎉
> Workflow run:
<https://github.com/appsmithorg/appsmith/actions/runs/11100769096>
> Commit: 46e043c998767acb456920f36459ae6f8968a267
> <a
href="https://internal.appsmith.com/app/cypress-dashboard/rundetails-65890b3c81d7400d08fa9ee5?branch=master&workflowId=11100769096&attempt=1"
target="_blank">Cypress dashboard</a>.
> Tags: `@tag.Sanity`
> Spec:
> <hr>Mon, 30 Sep 2024 07:14:51 UTC
<!-- end of auto-generated comment: Cypress test results  -->


/ok-to-test tags="@tag.Sanity"

deploy/docker/fs/opt/appsmith/utils/bin/move-to-postgres.mjs

@@ -91,7 +91,7 @@ for await (const collectionName of sortedCollectionNames) {
     if (isArchivedObject(doc)) {
       continue;
     }
-    transformFields(doc);
+    transformFields(doc);  // This now handles the _class to type transformation.
     if (doc.policyMap == null) {
       doc.policyMap = {};
     }
@@ -147,16 +147,39 @@ function replacer(key, value) {
  * Method to transform the data in the object to be compatible with Postgres.
  * Updates:
  * 1. Changes the _id field to id, and removes the _id field.
+ * 2. Replaces the _class field with the appropriate type field.
  * @param {Document} obj - The object to transform.
  * @returns {void} - No return value.
  */
 function transformFields(obj) {
   for (const key in obj) {
-    if (key === "_id") {  // Change the _id field to id
+    if (key === "_id") {
       obj.id = obj._id.toString();
       delete obj._id;
-    } else if (typeof obj[key] === "object") {
+    } else if (key === "_class") {
+      const type = mapClassToType(obj._class);
+      if (type) {
+        obj.type = type;  // Add the type field
+      }
+      delete obj._class;  // Remove the _class field
+    } else if (typeof obj[key] === "object" && obj[key] !== null) {
       transformFields(obj[key]);
     }
   }
-}
+}
+
+/**
+ * Map the _class field to the appropriate type value. The DatasourceStorage class requires this check
+ * @param {string} _class - The _class field value.
+ * @returns {string|null} - The corresponding type value, or null if no match is found.
+ */
+function mapClassToType(_class) {
+  switch (_class) {
+    case "com.appsmith.external.models.DatasourceStructure$PrimaryKey":
+      return "primary key";
+    case "com.appsmith.external.models.DatasourceStructure$ForeignKey":
+      return "foreign key";
+    default:
+      return null;
+  }
+}