feat(ctb): nicer error for wrong RPC

Gives users a nicer error when they provide the L2 RPC endpoint for the
L1 node.

.changeset/metal-clouds-watch.md

+---
+'@eth-optimism/data-transport-layer': patch
+---
+
+Give users a nicer revert when connected to wrong RPC

packages/data-transport-layer/src/services/l1-ingestion/service.ts

 /* Imports: External */
-import { fromHexString, sleep } from '@eth-optimism/core-utils'
+import { fromHexString, getChainId, sleep } from '@eth-optimism/core-utils'
 import { BaseService, Metrics } from '@eth-optimism/common-ts'
 import { TypedEvent } from '@eth-optimism/contracts/dist/types/common'
 import { BaseProvider, StaticJsonRpcProvider } from '@ethersproject/providers'
@@ -123,6 +123,14 @@ export class L1IngestionService extends BaseService<L1IngestionServiceOptions> {
       this.state.l1RpcProvider = this.options.l1RpcProvider
     }
 
+    // Make sure that the given provider is connected to L1 and not L2
+    const connectedChainId = await getChainId(this.state.l1RpcProvider)
+    if (connectedChainId === this.options.l2ChainId) {
+      throw new Error(
+        `Given L1 RPC provider is actually an L2 provider, please provide an L1 provider`
+      )
+    }
+
     this.logger.info('Using AddressManager', {
       addressManager: this.options.addressManager,
     })