[TASK] Skip empty content element

[twoldanski]

• align Content Object with Core version

[coveralls]

Pull Request Test Coverage Report for Build 7786467536

• -4 of 4 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.1%) to 64.248%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
Classes/ContentObject/JsonContentContentObject.php	0	4	0.0%
<!--	Total:	0	4	0.0%	-->

Totals
Change from base Build 7786293432:	-0.1%
Covered Lines:	841
Relevant Lines:	1309

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💛 - Coveralls