Fix Flaky Test in `polkadotjs_test `

## Describe the bug

- https://github.com/ChainSafe/gossamer/runs/7844762885?check_suite_focus=true

```
start_polkadotjs_test.go:65:
Error Trace: /go/src/github.com/ChainSafe/gossamer/tests/polkadotjs_test/start_polkadotjs_test.go:65
Error: Received unexpected error:
exit status 1
Test: TestStartGossamerAndPolkadotAPI
Messages:

Testing polkadot.js/api calls:
api constants
2022-08-15 19:36:19 RPC-CORE: getRuntimeVersion(at?: BlockHash): RuntimeVersion:: -32000: failed to get runtime instance: null
2022-08-15 19:36:19 API/INIT: Error: FATAL: Unable to initialize the API: -32000: failed to get runtime instance: null
at ApiPromise._onProviderConnect2 (/go/src/github.com/ChainSafe/gossamer/tests/polkadotjs_test/node_modules/@polkadot/api/cjs/base/Init.js:431:19)
at processTicksAndRejections (internal/process/task_queues.js:95:5)
2022-08-15 19:36:19 RPC-CORE: getMetadata(at?: BlockHash): Metadata:: -32000: failed to get runtime instance: null
start_polkadotjs_test.go:[60](https://github.com/ChainSafe/gossamer/runs/7844762885?check_suite_focus=true#step:3:61): Node alice-0 terminated
```