fix: prevent undefined or empty currencies from being queried (#5458)

## Explanation

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`CurrencyRateController` was getting an unexpected error when the
`NetworkController.networkConfigurationsByChainId` state included any
configuration with `nativeCurrency` set as `undefined`.

The easiest way to prevent this error, as well as to avoid unnecessary
results from the API that returns currency rates, is to filter out falsy
values of `nativeCurrency` when updating currency rates.

## References

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* Fixes #12345
* Related to #67890
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* Fixes
[#12583](MetaMask/metamask-mobile#12583)

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### `@metamask/assets-controllers`

- **FIXED**: Falsy values of `nativeCurrency` skipped when updating
currency rates.

## Checklist

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

Author: bergarces

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

@@ -537,4 +537,39 @@ describe('CurrencyRateController', () => {
 
     controller.destroy();
   });
+
+  it('skips updating empty or undefined native currencies', async () => {
+    jest.spyOn(global.Date, 'now').mockImplementation(() => getStubbedDate());
+    const cryptoCompareHost = 'https://min-api.cryptocompare.com';
+    nock(cryptoCompareHost)
+      .get('/data/pricemulti?fsyms=ETH&tsyms=xyz') // fsyms query only includes non-empty native currencies
+      .reply(200, {
+        ETH: { XYZ: 1000 },
+      })
+      .persist();
+
+    const messenger = getRestrictedMessenger();
+    const controller = new CurrencyRateController({
+      messenger,
+      state: { currentCurrency: 'xyz' },
+    });
+
+    const nativeCurrencies = ['ETH', undefined, ''];
+
+    await controller.updateExchangeRate(nativeCurrencies);
+
+    const conversionDate = getStubbedDate() / 1000;
+    expect(controller.state).toStrictEqual({
+      currentCurrency: 'xyz',
+      currencyRates: {
+        ETH: {
+          conversionDate,
+          conversionRate: 1000,
+          usdConversionRate: null,
+        },
+      },
+    });
+
+    controller.destroy();
+  });
 });

packages/assets-controllers/src/CurrencyRateController.ts

@@ -157,7 +157,9 @@ export class CurrencyRateController extends StaticIntervalPollingController<Curr
    *
    * @param nativeCurrencies - The native currency symbols to fetch exchange rates for.
    */
-  async updateExchangeRate(nativeCurrencies: string[]): Promise<void> {
+  async updateExchangeRate(
+    nativeCurrencies: (string | undefined)[],
+  ): Promise<void> {
     const releaseLock = await this.mutex.acquire();
     try {
       const { currentCurrency } = this.state;
@@ -167,6 +169,10 @@ export class CurrencyRateController extends StaticIntervalPollingController<Curr
       const testnetSymbols = Object.values(TESTNET_TICKER_SYMBOLS);
       const nativeCurrenciesToFetch = nativeCurrencies.reduce(
         (acc, nativeCurrency) => {
+          if (!nativeCurrency) {
+            return acc;
+          }
+
           acc[nativeCurrency] = testnetSymbols.includes(nativeCurrency)
             ? FALL_BACK_VS_CURRENCY
             : nativeCurrency;