Metadata import - store the validation status when the validation option is selected

[josegar74]

Test case:

1. Import a valid xml or MEF file, checking the Validate option.

2. In the editor boards, the metadata validation icon should be green, but without this change the icon is displayed as gray (no validation tested)

With the change:

In the original code the Validate option was used to discard the metadata if not valid, but the metadata status when the metadata is valid was not stored.