Gutenberg: update to v1.19.0

[cameronvoell]

Gutenberg-mobile PR: wordpress-mobile/gutenberg-mobile#1667

Changes:

• New block "Gallery". You can now create image galleries using WordPress Media library. Add Gallery Block gutenberg-mobile#1498
• Fix crash dismissing bottom-sheet after device rotation. Fix crash dismissing bottom-sheet on iOS after device rotation gutenberg-mobile#1628
• Add support for changing Settings in the List Block. Implement list settings gutenberg-mobile#1619
• Add support for Video block settings Implement video block settings gutenberg-mobile#1601

PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

You can trigger an installable build for these changes by visiting CircleCI here.

[pinarol]

I've tested this with the peril link on real device.

Below items look good to me:

• New block "Gallery". You can now create image galleries using WordPress Media library.
• Fix crash dismissing bottom-sheet after device rotation.
• Add support for changing Settings in the List Block.

I did some other smoke testing as well and couldn't caught anything odd. But it'd be good if someone else also checks it.

[mchowning]

Tested and looks good.