Adam Skelton 43e71ae64f
Include transform in static Gradient lerp methods (#149624)
*Fixes #149534 Gradient subclasses' static lerp methods drop the GradientTransform of both `a` and `b`*

LinearGradient.lerp(), RadialGradient.lerp() and SweepGradient.lerp() no longer drop the GradientTransform of `a` and/or `b`.

The primitive interpolation is performed the same way TileMode is handled:  `transform: t < 0.5 ? a.transform : b.transform`.

## Media

<details>
<summary>Video demonstration</summary>

### Before
https://github.com/flutter/flutter/assets/65806473/de14e201-b1a7-44ba-95ff-e62587c7f6ac

### After
https://github.com/flutter/flutter/assets/65806473/d48f40e2-1b0f-4ac8-a45c-b3c423e3fd64

</details>

  - Changed no documentation.
  - Non-breaking change.
2024-06-14 00:31:23 +00:00
..
2024-06-13 23:48:35 +00:00