Update error message for undefined GraphQL endpoint for actions/events #3383

Job	Run time
Build-And-Test-Server (Simple integration tests)	13m 53s
Build-And-Test-Server (DEX integration tests)	13m 48s
Build-And-Test-Server (DEX integration test with proofs)	13m 15s
Build-And-Test-Web	5m 0s
Build-And-Test-Server (Voting integration tests)	5m 42s
Build-And-Test-Server (Unit tests)	40m 19s
Build-And-Test-Server (Verification Key Regression Check)	10m 53s
Build-And-Test-Server (CommonJS test)	2m 57s
Release-mina-signer-on-NPM	2m 6s
Release-on-NPM	2m 8s
	1h 50m 1s

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