feat: add shared EstimatedChanges UI component - #369

Explanation

Adds a shared EstimatedChanges Snaps JSX component to @metamask/snap-networks-utils.

The component consolidates the common transaction-confirmation UI for:

Estimated changes header and tooltip
Send and receive asset groups
Asset amount and logo display
Loading and fetching states
Scan error state
Empty estimated-changes state
Unknown asset amounts
The component accepts display-ready assets and translated labels, allowing each Snap to retain ownership of network-specific formatting and localization.

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