fix: Network URL toPunycodeUrl preserve no path slash (#29325)

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## **Description**

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## **Related issues**

Related to: #29322

## **Manual testing steps**

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

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## **Pre-merge reviewer checklist**

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ui/pages/confirmations/confirmation/templates/add-ethereum-chain.test.js

@@ -159,6 +159,7 @@ describe('add-ethereum-chain confirmation', () => {
           "Attackers sometimes mimic sites by making small changes to the site address. Make sure you're interacting with the intended site before you continue. Punycode version: https://xn--ifura-dig.io/gnosis",
         ),
       ).toBeInTheDocument();
+      expect(getByText('https://iոfura.io/gnosis')).toBeInTheDocument();
     });
   });
 });

ui/pages/confirmations/utils/confirm.test.ts

@@ -93,16 +93,19 @@ describe('confirm util', () => {
       expect(toPunycodeURL('https://iոfura.io/gnosis')).toStrictEqual(
         'https://xn--ifura-dig.io/gnosis',
       );
-      expect(toPunycodeURL('https://www.google.com')).toStrictEqual(
-        'https://www.google.com/',
+      expect(toPunycodeURL('https://iոfura.io')).toStrictEqual(
+        'https://xn--ifura-dig.io',
+      );
+      expect(toPunycodeURL('https://iոfura.io/')).toStrictEqual(
+        'https://xn--ifura-dig.io/',
       );
       expect(
         toPunycodeURL('https://iոfura.io/gnosis:5050?test=iոfura&foo=bar'),
       ).toStrictEqual(
         'https://xn--ifura-dig.io/gnosis:5050?test=i%D5%B8fura&foo=bar',
       );
       expect(toPunycodeURL('https://www.google.com')).toStrictEqual(
-        'https://www.google.com/',
+        'https://www.google.com',
       );
     });
   });

ui/pages/confirmations/utils/confirm.ts

@@ -80,7 +80,12 @@ export const isValidASCIIURL = (urlString?: string) => {
 
 export const toPunycodeURL = (urlString: string) => {
   try {
-    return new URL(urlString).href;
+    const url = new URL(urlString);
+    const { protocol, hostname, port, search, hash } = url;
+    const pathname =
+      url.pathname === '/' && !urlString.endsWith('/') ? '' : url.pathname;
+
+    return `${protocol}//${hostname}${port}${pathname}${search}${hash}`;
   } catch (err: unknown) {
     console.error(`Failed to convert URL to Punycode: ${err}`);
     return undefined;