fix(native): expand a transition held in a variable

[YevheniiKotyrlo]

Problem

A transition held in a variable never reaches React Native as a transition:

• transition: var(--t) with --t: width 1s ease-in 200ms renders { transition: ["width", 1000, "ease-in", 200] }, where the written value renders transitionProperty, transitionDuration, transitionDelay and transitionTimingFunction.
• transition-property: var(--p) names the CSS properties as written, ["width", "background-image", "border-inline-start-color"], and no style key is spelled that way.

The written path names a transition by the property's camelCase rather than by the key the property is written to, so transition-property: background-image names backgroundImage where the style is experimental_backgroundImage, and border-inline-start-color names borderInlineStartColor where it is borderStartColor. Such a transition never matches the style it was written for.

Solution

• propertyRename moves to utilities beside toRNProperty, and transitionStyleKey names the key a transition animates, for the compiler and the runtime alike.
• transition and transition-property resolve at runtime when written with a var(). The transition resolver reads each comma group by CSS Transitions 1 §2.5 — any order, the first time the duration and the second the delay — into the longhands the compiler builds for a written value, and gives up on a group that is not a transition. transitionProperty maps a variable's names through transitionStyleKey.

A list whose every group is one token reaches the runtime without its commas, so width opacity reads as width, opacity, the only reading a valid transition allows; keeping the separator is a change of its own.

Tests

• src/__tests__/native/transition-variables.test.tsx renders a written transition and the same value through a variable, for seven values: one transition, a list, properties alone, cubic-bezier(), a renamed property, all and a time alone. It also covers the keys a written and a variable transition-property name, and two invalid variable values. All 11 fail on main.
• src/__tests__/utilities/property-names.test.ts holds every renamed property's transition to the key it is written to.

Verification

On Ubuntu with the workflow's steps - build, lint, typecheck, yarn test, node --test node/__tests__/*.mjs, both library builds, the web export, the unstaged-changes checks and commitlint - everything passes.

Merge order

Stacked on #491, which gives toRNProperty the utilities home this extends, so #491 lands first.