chore: intersection with ObserverMixin not required

Intersection with ObserverMixin not required anymore
Vary callback type
Signed-off-by: Hage Yaapa <hage.yaapa@in.ibm.com>

packages/repository/src/repositories/legacy-juggler-bridge.ts

@@ -50,7 +50,6 @@ export namespace juggler {
   export import Transaction = legacy.Transaction;
   // eslint-disable-next-line no-shadow
   export import IsolationLevel = legacy.IsolationLevel;
-  export import ObserverMixin = legacy.ObserverMixin;
 }
 
 function isModelClass(
@@ -101,8 +100,7 @@ export class DefaultCrudRepository<
   ID,
   Relations extends object = {}
 > implements EntityCrudRepository<T, ID, Relations> {
-  // Will just need juggler.PersistedModelClass once https://github.com/strongloop/loopback-datasource-juggler/issues/1824 is addressed
-  modelClass: juggler.PersistedModelClass & juggler.ObserverMixin;
+  modelClass: juggler.PersistedModelClass;
 
   public readonly inclusionResolvers: Map<
     string,
@@ -135,8 +133,7 @@ export class DefaultCrudRepository<
   // Create an internal legacy Model attached to the datasource
   private ensurePersistedModel(
     entityClass: typeof Model,
-    // Will just need juggler.PersistedModelClass once https://github.com/strongloop/loopback-datasource-juggler/issues/1824 is addressed
-  ): typeof juggler.PersistedModel & juggler.ObserverMixin {
+  ): typeof juggler.PersistedModel {
     const definition = entityClass.definition;
     assert(
       !!definition,
@@ -148,8 +145,7 @@ export class DefaultCrudRepository<
     const model = dataSource.getModel(definition.name);
     if (model) {
       // The backing persisted model has been already defined.
-      // Will just need juggler.PersistedModelClass once https://github.com/strongloop/loopback-datasource-juggler/issues/1824 is addressed
-      return model as typeof juggler.PersistedModel & juggler.ObserverMixin;
+      return model as typeof juggler.PersistedModel;
     }
 
     return this.definePersistedModel(entityClass);
@@ -163,8 +159,7 @@ export class DefaultCrudRepository<
    */
   protected definePersistedModel(
     entityClass: typeof Model,
-    // Will just need juggler.PersistedModelClass once https://github.com/strongloop/loopback-datasource-juggler/issues/1824 is addressed
-  ): typeof juggler.PersistedModel & juggler.ObserverMixin {
+  ): typeof juggler.PersistedModel {
     const dataSource = this.dataSource;
     const definition = entityClass.definition;
 
@@ -193,10 +188,7 @@ export class DefaultCrudRepository<
       }
       properties[key] = Object.assign({}, value);
     });
-    const modelClass = dataSource.createModel<
-      // Will just need juggler.PersistedModelClass once https://github.com/strongloop/loopback-datasource-juggler/issues/1824 is addressed
-      juggler.PersistedModelClass & juggler.ObserverMixin
-    >(
+    const modelClass = dataSource.createModel<juggler.PersistedModelClass>(
       definition.name,
       properties,
       Object.assign(