Add tests for mongoose child schema
Add tests for mongoose child schema

Fixes #20331

markogresak/DefinitelyTyped,aciccarello/DefinitelyTyped,arusakov/DefinitelyTyped,rolandzwaga/DefinitelyTyped,AgentME/DefinitelyTyped,dsebastien/DefinitelyTyped,zuzusik/DefinitelyTyped,georgemarshall/DefinitelyTyped,zuzusik/DefinitelyTyped,one-pieces/DefinitelyTyped,AbraaoAlves/DefinitelyTyped,rolandzwaga/DefinitelyTyped,AgentME/DefinitelyTyped,benliddicott/DefinitelyTyped,magny/DefinitelyTyped,AgentME/DefinitelyTyped,georgemarshall/DefinitelyTyped,arusakov/DefinitelyTyped,laurentiustamate94/DefinitelyTyped,alexdresko/DefinitelyTyped,alexdresko/DefinitelyTyped,arusakov/DefinitelyTyped,chrootsu/DefinitelyTyped,georgemarshall/DefinitelyTyped,dsebastien/DefinitelyTyped,AbraaoAlves/DefinitelyTyped,chrootsu/DefinitelyTyped,zuzusik/DefinitelyTyped,AbraaoAlves/DefinitelyTyped,AgentME/DefinitelyTyped,borisyankov/DefinitelyTyped,georgemarshall/DefinitelyTyped,aciccarello/DefinitelyTyped,aciccarello/DefinitelyTyped,magny/DefinitelyTyped,mcliment/DefinitelyTyped,borisyankov/DefinitelyTyped