Append the TextAnimatorNode as a child keypath

[ejensen]

Appends the TextAnimatorNode as a child keypath of TextCompositionLayer
This allows for setting values on text animations. For example Fill Color, Stroke Color, Stroke Width, and Tracking.

Animation keypaths before the change:

Lottie: Logging Animation Keypaths
Text Layer 1
Text Layer 1.Transform
Text Layer 1.Transform.Opacity
Text Layer 1.Transform.Rotation
Text Layer 1.Transform.Anchor Point
Text Layer 1.Transform.Scale
Text Layer 1.Transform.Position

Animation keypaths after the change:

Lottie: Logging Animation Keypaths
Text Layer 1
Text Layer 1.Transform
Text Layer 1.Transform.Opacity
Text Layer 1.Transform.Rotation
Text Layer 1.Transform.Anchor Point
Text Layer 1.Transform.Scale
Text Layer 1.Transform.Position
Text Layer 1.Animation 1
Text Layer 1.Animation 1.Fill Color