fix: use typed amount for Money Account max source calculations

[jpuri]

Explanation

When isMaxAmount is true, calculateSourceAmount substitutes the pay token's on-chain balanceRaw as the quote source. For deposits funded from the Money account (e.g. Send to Perps), that balance is only un-vaulted mUSD, not the full withdrawable total (mUSD + vmUSD). Clients were forced to keep isMaxAmount=false to avoid collapsing Max, which also forced EXPECTED_OUTPUT quotes and caused Max amount + fees to exceed balance ("Insufficient funds" / "Add less or use a different payment method").

This change skips the on-chain balance substitution when paymentOverride === MoneyAccount, so Max continues to use the typed required amount (already set from the full withdrawable total). Clients can then set isMaxAmount=true again and get EXACT_INPUT fee-aware Max quotes.

References

• Related mobile PR: fix: enable EXACT_INPUT Max for Money Account Send to Perps metamask-mobile#33974

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

Made with Cursor

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, have a team admin enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 9ae8ee3. Configure here.}