* bump zombienet version
* remove redundant 'is up' assertion
* bump zombienet version
* bump to latest version of zombienet
* add more time to check peers
* Decrease expected peer count in zombinenet tests
Recent change in the in/out peer ratio caused some of the zombienet
tests to fail. Adjust the number of expected peers to reflect the new
ratio to make tests pass again.
* Increase `--out-peers` to 15 for paritydb test
* Don't check the number of connected peers