Odoo Release Updates

[FIX] mail,*: revert faulty `this` added by migration script

[REF] mail_*: run owl3 rendering context migration script

[IMP] im_livechat: toast notification for live chat rating

[IMP] im_livechat: group all live chats in a single sidebar category

[FIX] im_livechat: prevent crash when using chatbot with website editor

[FIX] mail, hr_holidays, portal: send `partner_id` of `main_user_id`

[FIX] im_livechat: stabilize non-member operator description test

[FIX] mail: reduce spacing between lang and badge of livechat items

[REF] hr, *: run rendering context migration script

[REF] mail, im_livechat: use user in channel._broadcast

[REF] *: Run script to replace t-model by t-custom-model

[REF] *: Run script to replace t-ref by t-custom-ref

[FIX] im_livechat: fix chat bot double restart

[FIX] im_livechat: rephrase chatbot completion message in composer

[IMP] im_livechat: update menu labels and add group-by filter

[REF] *: Run script to replace t-esc by t-out

[IMP] im_livechat: open file viewer in live chat shadow DOM

[FIX] im_livechat: avoid messaging menu category flicker

[REF] *: remove url from js file tours

[FIX] mail,im_livechat: allow non-member agents to edit live chat description

[FIX] *: ensure cleanup of mock server patches

[FIX] im_livechat: close demo livechat sessions for coherent info panel

[REF] bus, mail: use user rather than partner as bus target

[FIX] im_livechat: message 'add reaction' works correctly for visitors

[IMP] im_livechat: improve leave action wording

[IMP] mail: minor improvements to call settings panel

[IMP] mail,*: use Bookmark as the string for starred

[FIX] mail,*: member remove action updates

[FIX] web: formatFloatTime + use extractOptions in list/graph

[IMP] mail: add read-only channels