Poll observe mode value assertions in autotransact tests

These will fail since observe mode is not set synchronously. We could
wait and check the value, but this behavior is already covered by the
multidevice tests in the same topic so asserting here is unnecessary.

Test: atest CtsNfcTestCases:CardEmulationTest#testAutoTransact,testAutoTransactDynamic,testAutoTransactDynamic_walletRoleEnabled,testAutoTransact_walletRoleEnabled,testOffHostAutoTransactDynamic
Bug: 334147652
Merged-In: Ibd6d51bc466c4b2285832cebcd472d19de505bc0
Change-Id: Ibd6d51bc466c4b2285832cebcd472d19de505bc0