test(nextjs): Adjust build validator for newest Next.js canary

[lforst]

Fixes #11298

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback)	80.54 KB (-0.04% 🔽)
@sentry/browser (incl. Tracing, Replay)	71.88 KB (-0.03% 🔽)
@sentry/browser (incl. Tracing, Replay with Canvas)	75.68 KB (-0.02% 🔽)
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	65.43 KB (-0.02% 🔽)
@sentry/browser (incl. Tracing)	36.71 KB (+0.02% 🔺)
@sentry/browser (incl. browserTracingIntegration)	36.71 KB (+0.02% 🔺)
@sentry/browser (incl. feedbackIntegration)	31.38 KB (+0.06% 🔺)
@sentry/browser (incl. feedbackModalIntegration)	31.5 KB (+0.09% 🔺)
@sentry/browser (incl. feedbackScreenshotIntegration)	31.51 KB (+0.09% 🔺)
@sentry/browser (incl. sendFeedback)	27.45 KB (+0.06% 🔺)
@sentry/browser	22.61 KB (+0.1% 🔺)
CDN Bundle (incl. Tracing, Replay, Feedback)	74.98 KB (+0.11% 🔺)
CDN Bundle (incl. Tracing, Replay)	69.8 KB (+0.11% 🔺)
CDN Bundle (incl. Tracing)	36.35 KB (+0.13% 🔺)
CDN Bundle	23.97 KB (+0.14% 🔺)
CDN Bundle (incl. Tracing, Replay) - uncompressed	219.11 KB (+0.05% 🔺)
CDN Bundle (incl. Tracing) - uncompressed	109.67 KB (+0.1% 🔺)
CDN Bundle - uncompressed	70.94 KB (+0.04% 🔺)
@sentry/react (incl. Tracing, Replay)	71.86 KB (-0.01% 🔽)
@sentry/react	22.64 KB (+0.12% 🔺)

[mydea]

lol xD