Revert "define validium <> custom_token CI tests"

This reverts commit 13a7f11.

Author: zkzoomer

core/tests/highlevel-test-tools/tests/main-node-integration-test.test.ts

@@ -5,8 +5,7 @@ describe('Integration Test', () => {
     it(`for ${TESTED_CHAIN_TYPE} chain`, async () => {
         const testChain = await createChainAndStartServer(TESTED_CHAIN_TYPE, 'Main Node Integration Test');
         // Define some chain B used for interop tests
-        const secondChainType = TESTED_CHAIN_TYPE === 'validium' ? 'custom_token' : 'era';
-        const testSecondChain = await createChainAndStartServer(secondChainType, 'Main Node Integration Test');
+        const testSecondChain = await createChainAndStartServer('era', 'Main Node Integration Test');
 
         await runIntegrationTests(testChain.chainName, testSecondChain.chainName);
     });