Test against React 18 also #439

Job	Run time
Test browser-cljsjs on React 18	1m 9s
Test bundle-adv on React 19	1m 40s
Test bundle on React 19	1m 0s
Test browser-npm-prod on React 19	2m 9s
Test browser-cljsjs-prod on React 18	2m 41s
Test shadow-cljs-prod on React 19	1m 32s
Test browser-npm on React 19	1m 25s
Test node-npm on React 19	1m 4s
Test shadow-cljs-prod on React 18	1m 34s
Update docs	0s
Update site	-1s
Test bundle on React 19	1m 0s
Test bundle-adv on React 19	1m 40s
Test browser-npm on React 19	1m 25s
Test node-npm on React 19	1m 4s
Test shadow-cljs-prod on React 19	1m 32s
Test browser-cljsjs-prod on React 18	1m 42s
Test browser-npm-prod on React 19	2m 9s
Test browser-cljsjs on React 18	1m 9s
Test shadow-cljs-prod on React 18	1m 34s
Update docs	0s
Update site	0s
	27m 28s

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