[RNMobile] Bump Aztec-Android version to 1.6.3

[fluiddot]

What?

Bump Aztec library version to the latest version (1.6.3).

Why?

This PR is a follow-up of #47604 in order to update Android minSdkVersion to 24. The minSdkVersion parameter was updated in Aztec version 1.6.3, therefore to have this parameter with the same value across the Android libraries, we need to bump the Aztec version.

How?

Update Aztec version to version 1.6.3 in the react-native-aztec package.

Testing Instructions

Aztec is used to render the RichText component, so we'd need to test that no regressions have been introduced in blocks that use that component:

• Paragraph block
• Heading block
• Search block
• Pullquote block
• File block
• Button block
• Shortcode block
• Contact Info block
• Gallery block (caption element)
• Audio block (caption element)
• Video block (caption element)
• Embed block (caption element)

Regarding the new changes in Aztec 1.6.3, seems none of them that should impact the RichText component, so it's not needed to test a specific functionality apart from smoke testing the components listed above.

Testing Instructions for Keyboard

N/A

Screenshots or screencast

N/A

[github-actions]

Flaky tests detected in 13d698b.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/4066968964
📝 Reported issues:

• [Flaky Test] shouldn't conflict with server-side autosave #35176 in specs/editor/various/autosave.test.js

[jhnstn]

I followed the test plan in wordpress-mobile/WordPress-Android#17852 on the WordPress Android build in that PR.

Everything worked as expected

[fluiddot]

Heads up that I've updated the title to specify that the bump is for Aztec-Android, not Aztec in general.