TMDM-7975: "Previous execution tool bar becomes grayed after validation is over"

Fix incorrect handling of VALIDATION_END event.
(https://jira.talendforge.org/browse/TMDM-7975)
TMDM-7968: "match plan shows the constructed records score as empty"

Put at least one match result when a record has matched multiple records.
Update unit test asserts following behavior change.
(https://jira.talendforge.org/browse/TMDM-7968)