Jl/caip multichain/fix wallet eip155 eth account assignment (#27769)

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## **Description**

Sets and reads eth accounts from/to `wallet:eip155` scope 

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## **Related issues**

Fixes: MetaMask/MetaMask-planning#3485

## **Manual testing steps**

1. Go to this page...
2.
3.

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## **Pre-merge author checklist**

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Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask
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- [ ] I've completed the PR template to the best of my ability
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Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
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app/scripts/lib/multichain-api/adapters/caip-permission-adapter-eth-accounts.test.ts

@@ -42,11 +42,23 @@ describe('CAIP-25 eth_accounts adapters', () => {
             notifications: [],
             accounts: ['eip155:100:0x100'],
           },
+          'wallet:eip155': {
+            methods: [],
+            notifications: [],
+            accounts: ['wallet:eip155:0x5'],
+          },
         },
         isMultichainOrigin: false,
       });
 
-      expect(ethAccounts).toStrictEqual(['0x1', '0x2', '0x4', '0x3', '0x100']);
+      expect(ethAccounts).toStrictEqual([
+        '0x1',
+        '0x2',
+        '0x4',
+        '0x3',
+        '0x100',
+        '0x5',
+      ]);
     });
   });
 
@@ -87,6 +99,10 @@ describe('CAIP-25 eth_accounts adapters', () => {
             notifications: [],
             accounts: ['eip155:100:0x100'],
           },
+          'wallet:eip155': {
+            methods: [],
+            notifications: [],
+          },
         },
         isMultichainOrigin: false,
       };
@@ -128,6 +144,15 @@ describe('CAIP-25 eth_accounts adapters', () => {
             notifications: [],
             accounts: ['eip155:100:0x1', 'eip155:100:0x2', 'eip155:100:0x3'],
           },
+          'wallet:eip155': {
+            methods: [],
+            notifications: [],
+            accounts: [
+              'wallet:eip155:0x1',
+              'wallet:eip155:0x2',
+              'wallet:eip155:0x3',
+            ],
+          },
         },
         isMultichainOrigin: false,
       });

app/scripts/lib/multichain-api/adapters/caip-permission-adapter-eth-accounts.ts

@@ -12,6 +12,16 @@ import {
   ScopeString,
 } from '../scope';
 
+const isEip155ScopeString = (scopeString: ScopeString) => {
+  const { namespace, reference } = parseScopeString(scopeString);
+
+  return (
+    namespace === KnownCaipNamespace.Eip155 ||
+    (namespace === KnownCaipNamespace.Wallet &&
+      reference === KnownCaipNamespace.Eip155)
+  );
+};
+
 export const getEthAccounts = (caip25CaveatValue: Caip25CaveatValue) => {
   const ethAccounts: string[] = [];
   const sessionScopes = mergeScopes(
@@ -21,12 +31,9 @@ export const getEthAccounts = (caip25CaveatValue: Caip25CaveatValue) => {
 
   Object.entries(sessionScopes).forEach(([_, { accounts }]) => {
     accounts?.forEach((account) => {
-      const {
-        address,
-        chain: { namespace },
-      } = parseCaipAccountId(account);
+      const { address, chainId } = parseCaipAccountId(account);
 
-      if (namespace === KnownCaipNamespace.Eip155) {
+      if (isEip155ScopeString(chainId)) {
         ethAccounts.push(address);
       }
     });
@@ -42,9 +49,7 @@ const setEthAccountsForScopesObject = (
   const updatedScopesObject: ScopesObject = {};
 
   Object.entries(scopesObject).forEach(([scopeString, scopeObject]) => {
-    const { namespace } = parseScopeString(scopeString);
-
-    if (namespace !== KnownCaipNamespace.Eip155) {
+    if (!isEip155ScopeString(scopeString as ScopeString)) {
       updatedScopesObject[scopeString as ScopeString] = scopeObject;
       return;
     }

test/e2e/run-api-specs-multichain.ts

@@ -155,7 +155,7 @@ async function main() {
                   notifications: ['eth_subscription'],
                 },
                 'wallet:eip155': {
-                  accounts: [],
+                  accounts: [`wallet:eip155:${ACCOUNT_1}`],
                   methods: walletEip155Methods,
                   notifications: [],
                 },