[backport] Turbopack: don't treat metadata routes as RSC

[mischnic]

Backport #82911

Closes PACK-5480

[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #83804 will degrade performances by 7.41%

_{Comparing mischnic/backport-85ef363 (965bb6b) with canary (287b763)¹}

🎉 Hooray! codspeed-rust just leveled up to 2.10.1!

A heads-up, this is a breaking change and it might affect your current performance baseline a bit. But here's the exciting part - it's packed with new, cool features and promises improved result stability 🥳!
Curious about what's new? Visit our releases page to delve into all the awesome details about this new version.

Summary

❌ 9 regressions

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	build[date-fns-all]	2.2 s	2.3 s	-5.39%
❌	build[date-fns-single]	1.3 s	1.4 s	-4.94%
❌	build[framer-motion-all]	3 s	3.2 s	-7.41%
❌	build[framer-motion-single]	2.1 s	2.3 s	-6.91%
❌	build[joy]	2 s	2.1 s	-5.53%
❌	build[lucide-react-all]	8.6 s	9.2 s	-7.24%
❌	build[lucide-react-single]	863.1 ms	910 ms	-5.15%
❌	build[mui]	3 s	3.2 s	-6.04%
❌	build[shiki]	5.9 s	6.1 s	-3.71%

Footnotes

1. No successful run was found on next-15-5 (050bdf1) during the generation of this report, so canary (287b763) was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[ijjk]

Tests Passed

[krsjenswbp]

thạnks