[FIX] mail, *: significantly reduce number of useless renders

* = hr_holidays, im_livechat, website_livechat

A huge amount of components where rendered for no reason, notably when typing a
new message (at every key press), which significantly slowed down the interface.

There were 2 causes to this number of renders:
- OWL rendering all children automatically, even if their props didn't change,
  unless `shouldUpdate` is overridden, which is now done.
- `useStore` selectors being way too generous in what they observed

task-2399731

closes odoo/odoo#62703

Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/addons/mail/static/src/components/follower/follower.js b/addons/mail/static/src/components/follower/follower.js
index dc3e395f03c..bafcd88afc9 100644
--- a/addons/mail/static/src/components/follower/follower.js
+++ b/addons/mail/static/src/components/follower/follower.js
@@ -4,6 +4,7 @@ odoo.define('mail/static/src/components/follower/follower.js', function (require
 const components = {
     FollowerSubtypeList: require('mail/static/src/components/follower_subtype_list/follower_subtype_list.js'),
 };
+const useShouldUpdateBasedOnProps = require('mail/static/src/component_hooks/use_should_update_based_on_props/use_should_update_based_on_props.js');
 const useStore = require('mail/static/src/component_hooks/use_store/use_store.js');
 
 const { Component } = owl;
@@ -15,6 +16,7 @@ class Follower extends Component {
      */
     constructor(...args) {
         super(...args);
+        useShouldUpdateBasedOnProps();
         useStore(props => {
             const follower = this.env.models['mail.follower'].get(props.followerLocalId);
             return [follower ? follower.__state : undefined];