Notices generated by default-widgets.php

[Viper007Bond]

Really edge case since this is coming from a theme that is manually creating some widgets with missing parameters, but still might as well fix it.

Semi-related: #11606

[Viper007Bond]

There's likely more of these now that I think of it. Not sure if I really want to go down that rabbit hole...

[ocean90]

#16761

[Viper007Bond]

Thanks! I found that ticket and read through it but I thought it was a different issue. Re-reading it now I realize it's the same. :)