Support Astro 6

[JPeer264]

Description

Astro 6 is out: https://astro.build/blog/astro-6/

Let's see if our @sentry/astro SDK is Astro 6 compatible

[linear-code]

JS-1917

[Lms24]

Some initial work on this: #19745

[Lms24]

It seems like there's a bug in Astro 6.0.2 that breaks Astro server islands on the node adapter: withastro/astro#15753

Our e2e tests are running into this because we test against server islands on node. I suggest we skip these for now and re-enable them once the bug was fixed in Astro.

[Lms24]

There also seems to be a second bug that might relate to our tests needing adjustments for catch-all routes: withastro/astro#15840 though I still need to look into this more thoroughly

[CyberFlameGO]

On Cloudflare Workers, Sentry seems to break the whole worker with "Unknown Server Error" being presented when trying to access an Astro website (note: this does not affect miniflare/local testing)

[Lms24]

@CyberFlameGO is this purely related to Astro 6?