fix: cleanup log when fetching balances (#7429)

## Explanation

Cleans up warning log when fetching balances.

## References

* Fixes
[#12345](MetaMask/metamask-extension#37183)


## 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 communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/contributing.md#updating-changelogs)
- [ ] I've introduced [breaking
changes](https://github.com/MetaMask/core/tree/main/docs/breaking-changes.md)
in this PR and have prepared draft pull requests for clients and
consumer packages to resolve them

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Removes warning logs on failed chain balance fetches in
`RpcBalanceFetcher` and documents the change in the changelog.
> 
> - **Logging cleanup**
> - Remove warning logs for failed chain balance fetches in
`packages/assets-controllers/src/rpc-service/rpc-balance-fetcher.ts`
(skip rejected results without logging).
> - **Changelog**
> - Update `packages/assets-controllers/CHANGELOG.md` under “Changed” to
note the logging removal.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
6c2d0e1. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: sahar-fehri

packages/assets-controllers/CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Remove warning logs for failed chain balance fetches in RPC balance fetcher ([#7429](https://github.com/MetaMask/core/pull/7429))
 - Reduce severity of ERC721 metadata interface log from `console.error` to `console.warn` ([#7412](https://github.com/MetaMask/core/pull/7412))
   - Fixes [#24988](https://github.com/MetaMask/metamask-extension/issues/24988)
 - Bump `@metamask/transaction-controller` from `^62.4.0` to `^62.6.0` ([#7325](https://github.com/MetaMask/core/pull/7325), [#7430](https://github.com/MetaMask/core/pull/7430))

packages/assets-controllers/src/rpc-service/rpc-balance-fetcher.ts

@@ -191,9 +191,6 @@ export class RpcBalanceFetcher implements BalanceFetcher {
     chainResultsArray.forEach((chainResult) => {
       if (chainResult.status === 'fulfilled') {
         results.push(...chainResult.value);
-      } else {
-        // Log error but continue with other chains
-        console.warn('Chain processing failed:', chainResult.reason);
       }
     });