docs: update Roll Back a Patch page with new Arcade demo and 2-patch screenshots

[AbhishekDoshi26]

Updates the Roll Back a Patch documentation with a new interactive Arcade demo and refreshed screenshots reflecting the current 2-patch scenario (previously showed 3 patches).

Changes

src/content/docs/code-push/rollback.mdx

• Replaced the existing Arcade embed with the updated rollback demo
• Replaced rollback_patch3_active.png → rollback_patch2_active.png
• Replaced rollback_patch3_rolled_back.png → rollback_patch2_rolled_back.png
• Updated narrative text from "three patches" to "two patches"
• Updated all patch number references (patch 3 → patch 2, patch 2 → patch 1)
• Updated image alt text accordingly

src/content/docs/flutter-concepts/flutter-for-beginners.mdx

• Replaced patches.png → rollback_patch2_active.png

Demo

https://app.arcade.software/share/GlHfzbxcicw61ux4NCHx

[dawn-ducky]

@AbhishekDoshi26 please change the title to be sentence case not camel case.

[AbhishekDoshi26]

@AbhishekDoshi26 please change the title to be sentence case not camel case.

Done :)