[FIX] web: Can't save a x2m in list editable if contains a m2m_tags with a color field

m2m_tags in list editable view try to get color on validation, the field is invalid because the mutex is pending.
Fix: use internal_set_value (don't re-rendering)

Issue: steps to reproduce:
- Create a new instance, install "sale"
- Create a product "prepayment", service, invoice on ordered qties
- Create aproduct "project phase", service, invoice on delivered qties, manually track delivered qties
- Create a SO with once prepayment, and twice a line with "project phase". ( the name (description) of the lines should be "phase 1" and "phase 2" )
- Create invoice => The prepayment is invoiced
- Go back to the SO, try to change the delivered qties of the first phase to 1
- Save => error, odoo doesn't let you save.