Contribute to Fuselage UIKit for input size block in modal.

[RonLek]

As a GitHub app developer I Need to: contribute to multi-line input block for modal in Fuselage and Apps Engine So That: I can display formatted code within Rocket.Chat.

Acceptance Criteria

• [x] Propose new change to include size.
• [ ] Raise PRs contributing to Fuselage and Apps-Engine with expected changes.

[RonLek]

This is being tracked in a discussion here

[RonLek]

@samad-yar-khan please raise PRs to Fuselage and Apps-Engine for @ggazzo and @tassoevan to take a look.

[samad-yar-khan]

@RonLek I have raised the fuselage PR and the review is still pending. Once its reviewed I will start working on the Apps Engine PR so that the new elements can be used by RC apps.