UX Multichain: Fixed NaN USD issue under Eth when using Fiat (#18981)

* updated fiat value

* updated primary value in storybook

ui/components/multichain/multichain-token-list-item/__snapshots__/multichain-token-list-item.test.js.snap

@@ -56,7 +56,6 @@ exports[`MultichainTokenListItem should render correctly 1`] = `
         <p
           class="box mm-text mm-text--body-md box--flex-direction-row box--color-text-alternative"
         >
-          NaN
            
            
         </p>

ui/components/multichain/multichain-token-list-item/multichain-token-list-item.js

@@ -139,7 +139,7 @@ export const MultichainTokenListItem = ({
             </Text>
           </Box>
           <Text color={TextColor.textAlternative}>
-            {Number(primary).toFixed(3)} {tokenSymbol}{' '}
+            {primary} {tokenSymbol}{' '}
           </Text>
         </Box>
       </Box>

ui/components/multichain/multichain-token-list-item/multichain-token-list-item.stories.js

@@ -29,7 +29,7 @@ export default {
   },
   args: {
     secondary: '$9.80 USD',
-    primary: '88.00687889',
+    primary: '88.0068',
     tokenImage: './images/eth_logo.png',
     tokenSymbol: 'ETH',
     title: 'Ethereum',