fix: null check in ListenerCollection notify method

[kkocel]

Fix for the issue I've encountered in the wild:

Caused by: java.lang.NullPointerException: Cannot invoke "java.util.function.Consumer.accept(Object)" because "listener" is null
    at com.microsoft.playwright.impl.ListenerCollection.notify(ListenerCollection.java:44)
    at com.microsoft.playwright.impl.PageImpl.didClose(PageImpl.java:234)
    at com.microsoft.playwright.impl.PageImpl.handleEvent(PageImpl.java:222)
    at com.microsoft.playwright.impl.Connection.dispatch(Connection.java:292)
    at com.microsoft.playwright.impl.Connection.processOneMessage(Connection.java:211)
    at com.microsoft.playwright.impl.ChannelOwner.runUntil(ChannelOwner.java:118)
    at com.microsoft.playwright.impl.Connection.sendMessage(Connection.java:130)
    at com.microsoft.playwright.impl.ChannelOwner.sendMessage(ChannelOwner.java:106)
    at com.microsoft.playwright.impl.FrameImpl.fillImpl(FrameImpl.java:335)
    at com.microsoft.playwright.impl.FrameImpl.lambda$fill$14(FrameImpl.java:325)
    at com.microsoft.playwright.impl.LoggingSupport.lambda$withLogging$0(LoggingSupport.java:36)
    at com.microsoft.playwright.impl.LoggingSupport.withLogging(LoggingSupport.java:47)
    at com.microsoft.playwright.impl.ChannelOwner.withLogging(ChannelOwner.java:89)
    at com.microsoft.playwright.impl.LoggingSupport.withLogging(LoggingSupport.java:35)
    at com.microsoft.playwright.impl.FrameImpl.fill(FrameImpl.java:325)
    at com.microsoft.playwright.impl.LocatorImpl.fill(LocatorImpl.java:235)
    at com.microsoft.playwright.Locator.fill(Locator.java:2988)

[kkocel]

@microsoft-github-policy-service agree company="Paramount"

[yury-s]

Is this a fix for #1659 ?

[kkocel]

Is this a fix for #1659 ?

nope, it's another bug I've encountered

[kkocel]

@yury-s I've seen that some tests randomly crashed and I don't have permissions to restart them.

[yury-s]

@yury-s I've seen that some tests randomly crashed and I don't have permissions to restart them.

These are old flakes, your PR is fine.