Bump dart from `9c624c4` to `e74a295` in /app_dart (#1995)
Bump dart from `9c624c4` to `e74a295` in /app_dart (#1995)


flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon,flutter/cocoon