[FIX] web: search in m2o displays lost connection notification

In the PR 104415, we add the possibility to abort the name_search rpcs
which will be ignored.
Unfortunately, we forgot that xhr.abort performs a reject which will be
converted into an "XmlHttpRequestError abort" error. This error will
cause a notification "Connection lost. Trying to reconnect...".

Solution:
We revert the modifications in the abort function and in the m2o
we catch all the errors on the rpc name_search that we are going to
abort because they have no more use.

How to reproduce:
- Go to a form view with a m2o field
- Having a slow network or a lot of records in the m2o
- Enter several char in the m2o search bar

Before this commit:
A notification "Connection lost. Trying to reconnect..." is displayed.

After this commit:
There is no notification.

closes odoo/odoo#109500

X-original-commit: 7bff161ac5e916bf4d4eabe4f9ada9a147893cf2
Signed-off-by: Samuel Degueldre <sad@odoo.com>

addons/web/static/src/legacy/js/core/ajax.js

@@ -97,17 +97,11 @@ function _genericJsonRpc (fct_name, params, settings, fct) {
     });
 
     // FIXME: jsonp?
-    /**
-     * @param {Boolean} rejectError Returns an error if true. Allows you to cancel
-     *                  ignored rpc's in order to unblock the ui and not display an error.
-     */
-    promise.abort = function (rejectError = true) {
-        if (rejectError) {
-            rejection({
-                message: "XmlHttpRequestError abort",
-                event: $.Event('abort')
-            });
-        }
+    promise.abort = function () {
+        rejection({
+            message: "XmlHttpRequestError abort",
+            event: $.Event('abort')
+        });
 
         if (!shadow) {
             core.bus.trigger('rpc_response');

addons/web/static/src/legacy/js/fields/relational_fields.js

@@ -641,6 +641,10 @@ var FieldMany2One = AbstractField.extend({
         }
 
         if (this.lastNameSearch) {
+            this.lastNameSearch.catch((reason) => {
+                // the last rpc name_search will be aborted, so we want to ignore its rejection
+                reason.event.preventDefault();
+            })
             this.lastNameSearch.abort(false)
         }
         this.lastNameSearch = this._rpc({