[google_maps_flutter] remove unnecessary test

[cyanglaz]

Remove this test as it is duplicate of https://github.com/flutter/plugins/blob/master/packages/google_maps_flutter/google_maps_flutter/example/integration_test/google_maps_test.dart#L268
It is also incorrectly setup as it was never ran on CI

Fixes: flutter/flutter#76606

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[mvanbeusekom]

LGTM