fix(tasks): use document .save() instead of new Model() in repository update (#3440)

* fix(tasks): use document .save() instead of new Model() in repository update

Prevents duplicate document creation when the update function receives a
mongoose document without a recognized _id or with isNew still set.
Aligns tasks repository with the pattern already used by organizations
and memberships repositories.

Closes #3433

* fix(tasks): update JSDoc param type for update() to reflect Mongoose document requirement

Author: PierreBrisorgueil

modules/tasks/repositories/tasks.repository.js

@@ -42,10 +42,10 @@ const get = (id) => {
 /**
  * @function update
  * @description Data access operation to update an existing task in the database.
- * @param {Object} task - The task object containing the updated details.
+ * @param {import('mongoose').Document} task - The hydrated Mongoose Task document to update. Must support `.save()`.
  * @returns {Object} The updated task.
  */
-const update = (task) => new Task(task).save().then((doc) => doc.populate(defaultPopulate));
+const update = (task) => task.save().then((doc) => doc.populate(defaultPopulate));
 
 /**
  * @function remove