fix: add @plausible-analytics/tracker to Vite optimizeDeps

[danielroe]

@plausible-analytics/tracker only declares a module field in its package.json — it has no main or exports. This causes Vite's import analysis plugin to fail when resolving the package, particularly in Vitest/Nuxt test environments:

Error: Failed to resolve entry for package "@plausible-analytics/tracker".
The package may have incorrect main/module/exports specified in its package.json.

This is breaking CI in nuxt/nuxt.com and nuxt/nuxters with @nuxtjs/plausible v3.

this PR adds @plausible-analytics/tracker to vite.optimizeDeps.include in the module setup so Vite pre-bundles it correctly, regardless of the package's non-standard entry point configuration.

[johannschopplich]

@danielroe Thank you very much. 🙏

[danielroe]

you are very welcome ❤️

[johannschopplich]

Release v3.0.2 is on its way. Hopefully de-breaking the respective CI's.