[FIX] im_livechat: disable attachment upload via drag and drop

Before this commit:

Attachments are not properly supported in livechat, so there is no point in
allowing attachments to be uploaded via drag and drop.

After this commit:

Disable attachment upload via drag and drop in livechat channels.

Task-2824502

closes odoo/odoo#95761

X-original-commit: 1aed05eb1c50ee69b974a140b3080e38c802cb2f
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

addons/im_livechat/static/src/models/composer_view.js

@@ -0,0 +1,17 @@
+/** @odoo-module **/
+
+import { patchRecordMethods } from '@mail/model/model_core';
+import { clear } from '@mail/model/model_field_command';
+import '@mail/models/composer_view';
+
+patchRecordMethods('ComposerView', {
+    /**
+     * @override
+     */
+    _computeDropZoneView() {
+        if (this.composer.thread && this.composer.thread.channel_type === 'livechat') {
+            return clear();
+        }
+        return this._super();
+    },
+});

addons/im_livechat/static/tests/qunit_suite_tests/components/composer_tests.js

@@ -26,5 +26,23 @@ QUnit.test('livechat: no add attachment button', async function (assert) {
     );
 });
 
+QUnit.test('livechat: disable attachment upload via drag and drop', async function (assert) {
+    assert.expect(2);
+
+    const { createComposerComponent, messaging } = await start();
+    const thread = messaging.models['Thread'].create({
+        channel_type: 'livechat',
+        id: 10,
+        model: 'mail.channel',
+    });
+    await createComposerComponent(thread.composer);
+    assert.containsOnce(document.body, '.o_Composer', "should have a composer");
+    assert.containsNone(
+        document.body,
+        '.o_Composer_dropZone',
+        "composer linked to livechat should not have a dropzone"
+    );
+});
+
 });
 });