[Serializer] Add option to skip uninitialized typed properties

[derrabus]

Q	A
Feature PR	symfony/symfony#41615
PR author(s)	@vuryss
Merged in	5.4

[carsonbot]

Thank you for this issue.
There has not been a lot of activity here for a while. Has this been resolved?

[javiereguiluz]

Fixed in #15823.