[FIX] web_editor: join peer to peer on focus in resetEditor

The PR #110241 inadvertently re-introduce the attempt to connect
in collaboration when the editor was reset. The attempt should only
be made when the user focus on the editable.

The line
`this.$editable[0].addEventListener('focus', this._joinPeerToPeer);`
in `resetEditor` will handle that case.

closes odoo/odoo#112167

Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>