bruig: Crash on clipboard issue

[alexlyp]

report from user: I have a password safe app that automatically clears the clipboard when it locks after a timeout they coincided. I've seen it with another flutter app. I'm slightly guessing, but I have a feeling what happens is the paste starts, then it gets cleared out concurrent and ends up pasting a null or something.

So looks like there is probably an issue with the clipboard attempting to paste something that has been removed from the clipboard. Either the clipboard dep itself would need to be updated, or we can/should handle the situation in our code.