chore: Make job_browser_loader_tests a required test

[AbhiPrasad]

Noticed this when looking at https://github.com/getsentry/sentry-javascript/actions/runs/4914887268

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	21.01 KB (-0.01% 🔽)
@sentry/browser - ES5 CDN Bundle (minified)	65.62 KB (0%)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	19.55 KB (-0.01% 🔽)
@sentry/browser - ES6 CDN Bundle (minified)	58.08 KB (0%)
@sentry/browser - Webpack (gzipped + minified)	21.16 KB (0%)
@sentry/browser - Webpack (minified)	69.03 KB (0%)
@sentry/react - Webpack (gzipped + minified)	21.18 KB (0%)
@sentry/nextjs Client - Webpack (gzipped + minified)	49.09 KB (0%)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	28.64 KB (-0.01% 🔽)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	26.86 KB (0%)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	47.35 KB (+0.15% 🔺)
@sentry/replay - Webpack (gzipped + minified)	41.13 KB (+0.15% 🔺)
@sentry/browser + @sentry/tracing + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	66.3 KB (+0.12% 🔺)
@sentry/browser + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	59.18 KB (+0.13% 🔺)