Gutenberg: update to v1.26.0

[pinarol]

gutenberg-mobile: wordpress-mobile/gutenberg-mobile#2153
WPiOS: wordpress-mobile/WordPress-iOS#13878

To test:

Bug fix

• Fix: remove extra padding for post title and first Paragraph block Fix: remove extra padding for post title and first Paragraph block gutenberg-mobile#2095
• Layout Template Modal & Button block - Orientation fixes Layout Template Modal & Button block - Orientation fixes gutenberg-mobile#2086
• Fix: prevent ripple effect on slider cell in BottomSheet and disable it completely on iOS Fix: prevent ripple effect on slider cell in BottomSheet and disable it completely on iOS gutenberg-mobile#2023
• Correct slider step value Correct slider step value gutenberg-mobile#2119
• Fix typography breakage in master Fix typography breakage in master gutenberg-mobile#2149
• Align plus icon for the iOS Stepper control Align plus icon for the iOS Stepper control gutenberg-mobile#2116
  ℹ️iOS only but checked all was working on Android

New feature & Improvement

• New: Column block - Feat: Column block gutenberg-mobile#1661
• New: Blogger template - Blog layout template gutenberg-mobile#2114
• Layout Picker - Keyboard visibility improvements Layout Picker - Keyboard visibility improvements gutenberg-mobile#2123

PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered adding accessibility improvements for my changes.
• 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 optional UI/connected tests for these changes by visiting CircleCI here.

[peril-wordpress-mobile]

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

[pinarol]

Writing flow sanity check:

• Undo-redo (steps)
• Copy-paste (steps)
• Splitting blocks (steps)
• Multiline components (steps)
  ⚠️ Verse and Code are under the dev flag so they can't be tested
• Formatting on rich-text based components (steps)
  ⚠️ After this bug was reported I double checked and it happens on android as well.
• Block insertion (steps)

[geriux]

All tests done! ✅

[geriux]

FYI the gutenberg-mobile ref is behind one commit (Podfile lock update)

[geriux]

Tested the new build with:

• Correct colors usage in Button ✅