chore: add optional abtest property event for swap events

[sahar-fehri]

Explanation

Adds optional ab_tests context to swap/bridge metrics events, allowing attribution to specific A/B test experiments

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

Low Risk
Primarily adds optional metadata fields and propagation for analytics; behavioral changes are limited to event payload composition and should not affect transaction execution.

Overview
Adds optional A/B test attribution to Unified Swap/Bridge metrics by introducing ab_tests on bridge-controller event context/types and an abTests field on bridge-status-controller history items.

Bridge Status flows (startPollingForBridgeTxStatus, submitTx, submitIntent) now accept/propagate abTests, persist it in txHistory, and #trackUnifiedSwapBridgeEvent resolves ab_tests from either the call-site properties or stored history before emitting events; getPreConfirmationPropertiesFromQuote also conditionally includes ab_tests. Includes a unit test to verify ab_tests is pulled from history for tracked failure events, and updates both packages’ changelogs.

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