[MERGE][FIX] mail: several fixes in discuss, chat window, chatter

This merge fixes a crash in discuss, in addition to re-introduce some _quality of life_
features that have been mistakenly removed from the chatter and from chat windows:

### 1. No crash when searching messages

This was caused by the addition of moderated channels. In short, fetching twice
the same message was performing a re-render of the thread due to a mis-consideration
of a moderation status change. When the fetch reaches the fetch limit, the re-render is
considered as a "load more" fetch, which only works when there is at least one message
registered for the current search.

This is fixed by re-render when there is a change of moderation status only.

Task-ID 1910180

### 2. Easily mention followers and employees in chatter

When mentioning a user from the chatter in a document, it was always
fetching all partners in a arbitrary order. As a result, it was hard to mention
followers and employees.

This is fixed by re-introducing the previous behaviour on mentions, which
groups them by followers, then employees, then all partners.

Task-ID 1910111

### 3. Show message document link in chat window

When a message is linked to a document, it usually shows a
link next to the message. This still works in the Discuss app,
but not in chat windows.

This erroneous regression was caused by a refactoring.
This is fixed by re-introduced document links on messages in chat
windows.

Task-ID 1910119

closes odoo/odoo#28744

1 files changed, 14 insertions, 11 deletions

diff --git a/addons/mail/static/src/js/composers/basic_composer.js b/addons/mail/static/src/js/composers/basic_composer.js
index a6cdb39e2de..8a533cd4515 100644
--- a/addons/mail/static/src/js/composers/basic_composer.js
+++ b/addons/mail/static/src/js/composers/basic_composer.js
@@ -211,7 +211,8 @@ var BasicComposer = Widget.extend({
      * displayed to the user. If none of them match, then it will fetch for more
      * partner suggestions (@see _mentionFetchPartners).
      *
-     * @param {$.Deferred<Object[]>} prefetchedPartners
+     * @param {$.Deferred<Object[]>} prefetchedPartners list of list of
+     *   prefetched partners.
      */
     mentionSetPrefetchedPartners: function (prefetchedPartners) {
         this._mentionPrefetchedPartners = prefetchedPartners;
@@ -302,21 +303,23 @@ var BasicComposer = Widget.extend({
      */
     _mentionFetchPartners: function (search) {
         var self = this;
-        return $.when(this._mentionPrefetchedPartners).then(function (partners) {
+        return $.when(this._mentionPrefetchedPartners).then(function (prefetchedPartners) {
             // filter prefetched partners with the given search string
             var suggestions = [];
             var limit = self.options.mentionFetchLimit;
             var searchRegexp = new RegExp(_.str.escapeRegExp(mailUtils.unaccent(search)), 'i');
-            if (limit > 0) {
-                var filteredPartners = _.filter(partners, function (partner) {
-                    return partner.email && searchRegexp.test(partner.email) ||
-                           partner.name && searchRegexp.test(mailUtils.unaccent(partner.name));
-                });
-                if (filteredPartners.length) {
-                    suggestions.push(filteredPartners.slice(0, limit));
-                    limit -= filteredPartners.length;
+            _.each(prefetchedPartners, function (partners) {
+                if (limit > 0) {
+                    var filteredPartners = _.filter(partners, function (partner) {
+                        return partner.email && searchRegexp.test(partner.email) ||
+                            partner.name && searchRegexp.test(mailUtils.unaccent(partner.name));
+                    });
+                    if (filteredPartners.length) {
+                        suggestions.push(filteredPartners.slice(0, limit));
+                        limit -= filteredPartners.length;
+                    }
                 }
-            }
+            });
             if (!suggestions.length && !self.options.mentionPartnersRestricted) {
                 // no result found among prefetched partners, fetch other suggestions
                 suggestions = self._mentionFetchThrottled(