fix: update ExpectedCondition to extend java util Function
Fixes
[skip ci]
// NB: this originally extended Guava's Function interface since Java didn't have one. To avoid code
// such as "com.google.common.base.Function condition = ExpectedConditions.elementFound(By);"
// breaking at compile time, we continue to extend Guava's Function interface.
-public interface ExpectedCondition<T> extends Function<WebDriver, T> {}
+public interface ExpectedCondition<T> extends Function<WebDriver, T>, java.util.function.Function<WebDriver, T> {}
