Xray should check if there are invalid Pre-Condition mementos when accessing a Test Run page

The Xray should check if there are invalid Pre-Condition mementos when accessing a test run page.

If a Pre-Condition is deleted from the system while Xray is disabled, the mementos of a Test Run won't be updated leading to an error when accessing a Test Run with this kind of invalid mementos. The pre-condition mementos should be validated and if a Test Run contains any invalid pre-condition, a message should be presented giving the user the option to Merge or Reset the Test Run.