chore: bump next to 15.1.3 in the monorepo (#10211)

Bumps Next.js to the latest version `15.1.3`. This affects only internal
`package.json` files (in the root dir and test)

Fixes errors from here https://github.com/payloadcms/payload/pull/10209

test/dev.ts

@@ -1,3 +1,4 @@
+import nextEnvImport from '@next/env'
 import chalk from 'chalk'
 import { createServer } from 'http'
 import minimist from 'minimist'
@@ -58,6 +59,10 @@ if (shouldStartMemoryDB) {
   await startMemoryDB()
 }
 
+// This is needed to forward the environment variables to the next process that were created after loadEnv()
+// for example process.env.MONGODB_MEMORY_SERVER_URI otherwise app.prepare() will clear them
+nextEnvImport.updateInitialEnv(process.env)
+
 // Open the admin if the -o flag is passed
 if (args.o) {
   await open(`http://localhost:3000${adminRoute}`)