[FIX] base: browse(record) in company-dependent field value

The faulty code modifies a dictionary in-place to apply a formatting
function to each value.  In this case, the formatting is `browse`, and
the issue occurs when `ids` contain duplicates:

    for id in ids:
        result[id] = format(result.get(id, default))

Fix it by returning a new dictionary based on `result`.

X-original-commit: bd4565e2