fix(tron-wallet-snap): correct behavior for trc20 transfer type transactions

[gabrieledm]

Explanation

Fixes Tron transaction activity displaying 0 SUN or -0 SUN for SUN -> USDT swaps routed through Rango and SunSwap.

TronGrid returns a zero-value Approval event before the actual outgoing SUN Transfer.
The transaction mapper previously selected the first event sent by the account, causing the approval to be treated as the swap’s source leg.

Swap detection now considers only Transfer events when selecting source and destination token movements.
This preserves existing approval handling while displaying the actual SUN amount in activity history.

A regression test covers the reported event ordering and verifies that 276.791363098075785381 SUN -> 4.891342 USDT is mapped correctly.

Testing

• Added regression coverage for an approval event preceding the SUN transfer.
• Verified existing TRC-20 swap, send, receive, and approval tests.
• Ran the complete Tron wallet Snap test suite.
• Ran TypeScript, ESLint, formatting, and diff checks.

References

Fixes: WPN-1745

Before

After

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

[gabrieledm]

@metamaskbot publish-preview

[github-actions]

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@metamask-previews/bitcoin-wallet-snap@2.0.1-preview-05ea60a5
@metamask-previews/snap-networks-utils@1.0.0-preview-05ea60a5
@metamask-previews/solana-wallet-snap@5.0.1-preview-05ea60a5
@metamask-previews/tron-wallet-snap@3.0.0-preview-05ea60a5