Fix occasional flicker when transitioning a property

[martinbooth]

If transitionStyleHasChangedResult is true, the code in useLayoutEffect should run synchronously without rendering the style being transitioned to, but this doesn't appear to be the case 100% of the time because I've got one transition that momentarily shows the target style before running the transition. Even this doesn't repro reliably.

Even though I'd expect returning the current style if transitionStyleHasChangedResult is true to be a no-op (because the useLayoutEffect should cause a synchronous render with a new value), it doesn't seem to always be that way and this PR fixes the issue

[github-actions]

workflow: benchmarks/size

Comparison of minified (terser) and compressed (brotli) size results, measured in bytes. Smaller is better.

Results	Base	Patch	Ratio
react-strict-dom/dist/dom/index.js
· compressed	2,514	2,514	1.00
· minified	8,691	8,691	1.00
react-strict-dom/dist/dom/runtime.js
· compressed	855	855	1.00
· minified	2,435	2,435	1.00
react-strict-dom/dist/native/index.js
· compressed	16,177	16,182	1.00	+
· minified	60,356	60,373	1.00	+

[github-actions]

workflow: benchmarks/perf (native)

Comparison of performance test results, measured in operations per second. Larger is better.

Results	Base	Patch	Ratio
css.create
· small	1,078,524	1,084,347	1.01	+
· small with units	404,131	398,492	0.99	-
· small with variables	637,782	610,559	0.96	-
· several small	298,229	298,476	1.00	+
· large	193,239	189,565	0.98	-
· large with polyfills	136,383	135,135	0.99	-
· complex	93,876	92,080	0.98	-
· unsupported	204,935	204,265	1.00	-
css.createTheme
· simple theme	214,398	214,969	1.00	+
· polyfill theme	203,769	202,478	0.99	-
css.props
· small	278,929	272,016	0.98	-
· small with units	210,335	208,320	0.99	-
· small with variables	107,877	108,427	1.01	+
· small with variables of units	74,350	73,680	0.99	-
· large	119,567	118,706	0.99	-
· large with polyfills	38,842	38,848	1.00	+
· complex	23,703	23,844	1.01	+
· unsupported	168,487	170,591	1.01	+
· simple merge	173,643	174,806	1.01	+
· wide merge	17,915	18,408	1.03	+
· deep merge	17,709	17,876	1.01	+
· themed merge	34,315	34,601	1.01	+