Express relay tests (#54)

* add event check for multicall issued

* checkMulticallStatus function

* add toggle test

* add an actual multicall unit test

* multicall and callWifBid unit tests

* add internal tests

* add comments

* address comments

* small change

* got rid of assertExepctedBidPaymentTokenVault

* got rid of assertExepctedBidPaymentMockTarget

* further cleanup

* fix

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Co-authored-by: --systemdf <[email protected]>
Co-authored-by: --systemdf <[email protected]>