fix(assets-controller): hardened error handling

[Kriys94]

Explanation

References

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
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

---

Note

Medium Risk
Moderate risk because it changes how balance/detection/staked-balance update callbacks propagate failures, potentially masking bugs but preventing unhandled rejections from breaking polling ticks or subscriptions.

Overview
Improves resilience of assets-controller update pipelines by catching and logging errors inside subscription/polling callbacks instead of letting them throw/reject.

AssetsController now guards onActiveChainsUpdated, and RpcDataSource/StakedBalanceDataSource wrap balance, detection, and staked-balance update handlers so poll ticks can’t fail due to uncaught exceptions or unhandled promise rejections.

^{Reviewed by Cursor Bugbot for commit db04572. Bugbot is set up for automated code reviews on this repo. Configure here.}