Revert @metamask/transaction-pay-controller changes not required

[jpuri]

Explanation

Revert @metamask/transaction-pay-controller changes not required

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

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Note

High Risk
Marked breaking in the PR; changes MM Pay relay user identity and whether post-quote same-token transfers fetch quotes, which can break account-override and same-token MM Pay flows that depended on #9150/#9187.

Overview
Reverts recent MM Pay relay and post-quote behavior in @metamask/transaction-pay-controller.

Relay quotes: Removes getQuoteUser and always sets the quote body user to the resolved from address. Same-chain, same-token flows with accountOverride no longer send txParams.from as user on non–post-quote requests.

Post-quote source amounts: calculatePostQuoteSourceAmounts no longer skips same-token-on-same-chain filtering when isQuoteRequired is true. Post-quote paths again drop identical source/destination tokens unless isHyperliquidSource or isPolymarketDepositWallet applies. isQuoteRequired still affects non–post-quote source amount logic elsewhere.

Changelog and tests for the reverted behavior are updated accordingly.

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