feat(sveltekit): Add sentrySvelteKitPlugin

[Lms24]

This PR adds the sentrySvelteKitPlugin vite plugin to the SvelteKit SDK which will replace the withSentryViteConfig wrapper. Currently, this plugin does exactly what the wrapper is doing, namely, adding the injectInitPlugin. In the future, this plugin will also add the source maps plugin.

Usage:

// vite.config.ts|js
export default defineConfig({
  plugins: [sentrySvelteKitPlugin(), sveltekit()],
  // rest of config
});

I'll remove withSentryViteConfig in a follow-up PR, to keep the removal atomic.

ref #7787

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	20.94 KB (+0.08% 🔺)
@sentry/browser - ES5 CDN Bundle (minified)	65.44 KB (+0.03% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	19.49 KB (+0.08% 🔺)
@sentry/browser - ES6 CDN Bundle (minified)	57.88 KB (+0.04% 🔺)
@sentry/browser - Webpack (gzipped + minified)	21.11 KB (+0.06% 🔺)
@sentry/browser - Webpack (minified)	68.87 KB (+0.03% 🔺)
@sentry/react - Webpack (gzipped + minified)	21.14 KB (+0.07% 🔺)
@sentry/nextjs Client - Webpack (gzipped + minified)	48.9 KB (+0.03% 🔺)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	28.5 KB (+0.06% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	26.73 KB (+0.06% 🔺)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	44.89 KB (-0.07% 🔽)
@sentry/replay - Webpack (gzipped + minified)	38.85 KB (-0.06% 🔽)
@sentry/browser + @sentry/tracing + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	63.78 KB (-0.05% 🔽)
@sentry/browser + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	56.82 KB (-0.05% 🔽)

[AbhiPrasad]

should we think about removing this injection behaviour all together then?

[Lms24]

Yeah I was sort of debating if we should keep it as an alternative but I think the drawback is that we have to support both ways. Also the init location of hook vs. injected init calls differs slightly in the final bundles. Since IMO hooks are the better choice anyway, I'd say we remove it.

But I suggest we do it in a follow up PR, to make reverting easier if we have to, wdyt?

[AbhiPrasad]

let's do it in a follow up PR!