fix: fix mantle price when calling fetchMultiExchangeRate (#5099)

## Explanation

PR to fix the MANTLE price fetched for chainId: 5000.

Cryptocompare api provides prices for both MANTLE and MNT:
https://min-api.cryptocompare.com/data/pricemulti?fsyms=ETH%2CMNT%2CMANTLE&tsyms=usd
And it is returning the the price for 'MNT' when the user in on MANTLE
chain.


## References

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## Changelog

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### `@metamask/assets-controllers`

- **FIXED**: Added a check if any of the provided cyrptocurrencies to
`fetchMultiExchangeRate` fct exists in `nativeSymbolOverrides` map
- **ADDED**: Added utility function `getKeyByValue` to assetsUtils


## Checklist

- [ ] I've updated the test suite for new or updated code as appropriate
- [ ] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [ ] I've highlighted breaking changes using the "BREAKING" category
above as appropriate
- [ ] I've prepared draft pull requests for clients and consumer
packages to resolve any breaking changes

packages/assets-controllers/src/assetsUtil.test.ts

@@ -743,6 +743,17 @@ describe('assetsUtil', () => {
       }
     });
   });
+
+  describe('getKeyByValue', () => {
+    it('should return correct key for a specific value', () => {
+      const testMap = new Map([
+        ['toto', 'koko'],
+        ['foo', 'bar'],
+      ]);
+      const result = assetsUtil.getKeyByValue(testMap, 'koko');
+      expect(result).toBe('toto');
+    });
+  });
 });
 
 /**

packages/assets-controllers/src/assetsUtil.ts

@@ -433,3 +433,18 @@ export async function fetchTokenContractExchangeRates({
     {},
   );
 }
+
+/**
+ * Function to search for a specific value in a given map and return the key
+ * @param map - map input to search value
+ * @param value - the value to search for
+ * @returns returns key that corresponds to the value
+ */
+export function getKeyByValue(map: Map<string, string>, value: string) {
+  for (const [key, val] of map.entries()) {
+    if (val === value) {
+      return key;
+    }
+  }
+  return null; // Return null if no match is found
+}

packages/assets-controllers/src/crypto-compare-service/crypto-compare.test.ts

@@ -195,5 +195,21 @@ describe('CryptoCompare', () => {
         sol: { eur: 3000 },
       });
     });
+
+    it('should override native symbol for mantle native token', async () => {
+      nock(cryptoCompareHost)
+        .get('/data/pricemulti?fsyms=MANTLE,ETH&tsyms=EUR')
+        .reply(200, {
+          MANTLE: { EUR: 1000 },
+          ETH: { EUR: 2000 },
+        });
+
+      // @ts-expect-error Testing the case where the USD rate is not included
+      const response = await fetchMultiExchangeRate('EUR', ['MNT', 'ETH']);
+      expect(response).toStrictEqual({
+        eth: { eur: 2000 },
+        mnt: { eur: 1000 },
+      });
+    });
   });
 });

packages/assets-controllers/src/crypto-compare-service/crypto-compare.ts

@@ -1,5 +1,7 @@
 import { handleFetch } from '@metamask/controller-utils';
 
+import { getKeyByValue } from '../assetsUtil';
+
 /**
  * A map from native currency symbol to CryptoCompare identifier.
  * This is only needed when the values don't match.
@@ -141,11 +143,11 @@ export async function fetchMultiExchangeRate(
   cryptocurrencies: string[],
   includeUSDRate: boolean,
 ): Promise<Record<string, Record<string, number>>> {
-  const url = getMultiPricingURL(
-    cryptocurrencies,
-    [fiatCurrency],
-    includeUSDRate,
+  const fsyms = cryptocurrencies.map(
+    (nativeCurrency) =>
+      nativeSymbolOverrides.get(nativeCurrency) ?? nativeCurrency,
   );
+  const url = getMultiPricingURL(fsyms, [fiatCurrency], includeUSDRate);
   const response = await handleFetch(url);
   handleErrorResponse(response);
 
@@ -154,7 +156,8 @@ export async function fetchMultiExchangeRate(
     string,
     Record<string, number>,
   ][]) {
-    rates[cryptocurrency.toLowerCase()] = {
+    const key = getKeyByValue(nativeSymbolOverrides, cryptocurrency);
+    rates[key?.toLowerCase() ?? cryptocurrency.toLowerCase()] = {
       [fiatCurrency.toLowerCase()]: values[fiatCurrency.toUpperCase()],
       ...(includeUSDRate && { usd: values.USD }),
     };

packages/assets-controllers/src/index.ts

@@ -130,6 +130,7 @@ export {
   formatIconUrlWithProxy,
   getFormattedIpfsUrl,
   fetchTokenContractExchangeRates,
+  getKeyByValue,
 } from './assetsUtil';
 export {
   CodefiTokenPricesServiceV2,