Enable Spacer block in production

[geriux]

Updates Gutenberg so the Spacer block is available in production.

Gutenberg-> WordPress/gutenberg#18605

To test:

• Run the app without metro running
• Start a new post
• Select the Spacer block
  • Change the height of the Spacer
  • Move the block between other ones and check it works correctly
  • Remove the block
  • Add one again
• Save as draft
• Open your draft and check the Spacer block is shown correctly

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 test the changes on this Pull Request by downloading the APK here.

[marecar3]

Hey @geriux, when we bring some changes to WPAndroid app from the gutenberg mobile repo, it's always a good practice to start a branch name with a prefix gutenberg/ or gb/.

[geriux]

Hey @geriux, when we bring some changes to WPAndroid app from the gutenberg mobile repo, it's always a good practice to start a branch name with a prefix gutenberg/ or gb/.

Thanks for the suggestion 🙌 I'll keep this in mind for future PRs since this one won't be merged and it's just to test all is working ok