As an editor I want to be informed if my query is broken in order to fix it.

Problem:
The Query Builder might get into a state where we don't have a syntactically valid query. The user might still try to execute the query. We should inform them about the error.

Example:

• Not filled out value field (eventually we will want this to be possible in order to query for any value with a given Property)
• Value has been filled and then the Property removed afterwards
• No query has been provided

Screenshots/mockups:
Entirely empty UI

no property selected (but value is there)

no value selected (but property is there)

BDD
GIVEN an incomplete query
WHEN the user presses the run query button
THEN an error is shown and the field validation shows errors for the empty fields

GIVEN a completely empty query
WHEN the user presses the run query button
THEN a notice is shown

Acceptance criteria:

• we show helpful notice when user tries to run an empty query
• we show helpful error and field validation when user tries to run incomplete or syntactically wrong query

Notes:

• We decided against disabling the "Run query" button in those cases.
• requires the notice and error message component (T265264)