Subject diagnostics search fields remove default values "someSubjectId" etc.

The subject diagnostics search fields all pre-fill the subject search fields:

• subject ID: "someSubjectId"
• Subject Identifier: "someSubjectIdentifier"
• Search string: "first last"

These values are unlikely to find anyone, so the user has to go to the fields and overwrite them or delete the values, otherwise they will have errors. Why default values? If they need hints, we can add placeholder properties to the input fields (see mockup screenshot).