Bump next from 14.2.15 to 14.2.21 in /test/nextjs/app #150

Job	Run time
Validation	6s
JavaScript linter (Prettier)	33s
Git linter (Lintje)	2m 16s
Node.js 18 - Build	37s
Node.js 20 - Build	35s
Node.js 22 - Build	34s
Ruby linter (RuboCop)	8s
Integration tests (Express + Redis)	2m 56s
Integration tests (Express + Knex.js)	2m 7s
Integration tests (Koa + MySQL)	2m 32s
Integration tests (Koa + Mongo)	2m 12s
Integration tests (Express + Mongoose)	2m 0s
Integration tests (Express + Postgres)	1m 56s
Integration tests (Express + Apollo)	1m 58s
Integration tests (Express + Yoga)	1m 58s
Integration tests (Express + Prisma + Postgres)	2m 20s
Integration tests (Express + Prisma + Mongo)	2m 21s
Integration tests (Next.js)	2m 16s
Integration tests (Nest.js)	2m 4s
Integration tests (Fastify)	2m 14s
Node.js 22 - Tests	51s
Node.js 22 - Extra test - diagnose	2m 42s
Node.js 20 - Tests	51s
Node.js 20 - Extra test - diagnose	2m 43s
Node.js 18 - Tests	1m 3s
Node.js 18 - Extra test - diagnose	2m 59s
Node.js 22 - Clean up	0s
Node.js 20 - Clean up	0s
Node.js 18 - Clean up	0s
	44m 52s

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