Fix internal server error when querying without field (#957) #3205

Job	Run time
lint_core	20s
Build frontend unit test image	1m 0s
Build backend e2e test image	1m 18s
Build frontend e2e test image	2m 13s
Lint mwdb-core web sources	44s
Build mwdb-core core image	2m 18s
Build mwdb-core web image	33s
Perform frontend unit tests	30s
Perform frontend e2e tests	3m 26s
Perform backend e2e tests	3m 48s
Push test images on Docker Hub	44s
Push images on Docker Hub	3m 11s
	20m 5s

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