Startup benchmarks: allow notifications

[martinbonnin]

Without this, trying to run the benchmarks fails with

 E  java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object androidx.test.uiautomator.UiObject2.wait(androidx.test.uiautomator.UiObject2Condition, long)' on a null object reference
    	at com.google.samples.apps.nowinandroid.foryou.ForYouActionsKt.forYouWaitForContent(ForYouActions.kt:32)
    	at com.google.samples.apps.nowinandroid.startup.AbstractStartupBenchmark$startup$2.invoke(StartupBenchmark.kt:92)
    	at com.google.samples.apps.nowinandroid.startup.AbstractStartupBenchmark$startup$2.invoke(StartupBenchmark.kt:79)
    	at androidx.benchmark.macro.MacrobenchmarkKt$macrobenchmark$3$2.invoke(Macrobenchmark.kt:209)
    	at androidx.benchmark.macro.MacrobenchmarkKt$macrobenchmark$3$2.invoke(Macrobenchmark.kt:207)

I'm guessing because the permission popup hides the content below:

Now I'm wondering how much this popup biases the test in the first place cause we certainly don't want to measure the time to display the permission popup by the system?

Edit: I see there's some prior work here but unsure what the status is?

[tunjid]

Thanks for catching this!