refactor: remove unused end param in ethereum-chain-util helpers (#29619

)

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## **Description**

Removes unused `end` param in the ethereum-chain-util helpers
* validateChainId
* validateAddEthereumChainParams
* validateSwitchEthereumChainParams

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Extending E2E timeout to get past "no timings found" error:

```
flags = { "circleci": { "timeoutMinutes": 30 } }
```

## **Related issues**

See:
#27847 (comment)

## **Manual testing steps**

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app/scripts/lib/rpc-method-middleware/handlers/add-ethereum-chain.js

@@ -50,7 +50,7 @@ async function addEthereumChainHandler(
 ) {
   let validParams;
   try {
-    validParams = validateAddEthereumChainParams(req.params[0], end);
+    validParams = validateAddEthereumChainParams(req.params[0]);
   } catch (error) {
     return end(error);
   }

app/scripts/lib/rpc-method-middleware/handlers/ethereum-chain-utils.js

@@ -25,7 +25,7 @@ export function validateChainId(chainId) {
   return _chainId;
 }
 
-export function validateSwitchEthereumChainParams(req, end) {
+export function validateSwitchEthereumChainParams(req) {
   if (!req.params?.[0] || typeof req.params[0] !== 'object') {
     throw rpcErrors.invalidParams({
       message: `Expected single, object parameter. Received:\n${JSON.stringify(
@@ -43,10 +43,10 @@ export function validateSwitchEthereumChainParams(req, end) {
     });
   }
 
-  return validateChainId(chainId, end);
+  return validateChainId(chainId);
 }
 
-export function validateAddEthereumChainParams(params, end) {
+export function validateAddEthereumChainParams(params) {
   if (!params || typeof params !== 'object') {
     throw rpcErrors.invalidParams({
       message: `Expected single, object parameter. Received:\n${JSON.stringify(
@@ -75,7 +75,7 @@ export function validateAddEthereumChainParams(params, end) {
     });
   }
 
-  const _chainId = validateChainId(chainId, end);
+  const _chainId = validateChainId(chainId);
   if (!rpcUrls || !Array.isArray(rpcUrls) || rpcUrls.length === 0) {
     throw rpcErrors.invalidParams({
       message: `Expected an array with at least one valid string HTTPS url 'rpcUrls', Received:\n${rpcUrls}`,

app/scripts/lib/rpc-method-middleware/handlers/switch-ethereum-chain.js

@@ -36,7 +36,7 @@ async function switchEthereumChainHandler(
 ) {
   let chainId;
   try {
-    chainId = validateSwitchEthereumChainParams(req, end);
+    chainId = validateSwitchEthereumChainParams(req);
   } catch (error) {
     return end(error);
   }