This commit fix most `t-set` errors that either led to:
  1. unwanted text to be considered as translatable.
     eg: `<t t-set="classes">text-left bg-100 p4</t>` would create an
     `ir.translation`.
  2. text that should be translatable were not.
     eg: `<t t-set="text" t-value="'Both'"/>` would not create an
     `ir.translation` while it should.

If a text should be translatable, it should never be inside a `t-value`:
  - `<t t-set="text">Both</t>`
If a text should not be translatable, it sould either be inside `t-value`,
`t-valuef` or the `<t>` tag should have `t-translation="off"`:
  - `<t t-set="classes" t-translation="off">text-left bg-100 p4</t>`
  - `<t t-set="classes" t-valuef="text-left bg-100 p4"/>`
  - `<t t-set="classes" t-value="'text-left bg-100 p4'"/>`

https://github.com/odoo/odoo/pull/43660
https://github.com/odoo/enterprise/pull/7839
https://github.com/odoo/design-themes/pull/203



closes odoo/odoo#43660

Related: odoo/enterprise#7839
Signed-off-by: Romain Derie (rde) <rde@odoo.com>