[FIX] sale_timesheet: fix activity 'upsell' when threshold is not exceed

Description of the issue/feature this PR addresses:
In sale, when threshold value of product is not exceed than upsell activity is
created while creating invoice. upsell activity is only create when threshold
value exceed otherwise not.

Current behavior before PR:
When creating an invoice, an 'upsell' activity is created on the sales order and
assigned to the salesperson even if the threshold has not been exceeded.

Desired behavior after PR is merged:
Do not create a 'upsell' activity unless threshold is exceeded.

Fix:
super class is invoke before checking the upsell and create activity. so
now, we prevent super method from creating upsell activity via passing
`mail_activity_automation_skip` context.

task- 3330815

closes odoo/odoo#121740

Signed-off-by: Xavier Bol (xbo) <xbo@odoo.com>