[15.0][IMP+FIX] dms: Improve performance + Avoid non-existing record access error

[victoralmau]

Improve performance + Avoid non-existing record access error

Changes done:

• [x] Improve _dms_operations() method to do nothing if the model is not one of those used in dms.storage.
• [x] Avoid access error with .browse() if we access a non-existing record (for example, deleted by database).

Please @pedrobaeza and @chienandalu can you review it?

@Tecnativa TT50231