chore: remove dead telemetry code (#47950)

## Summary
Removes two pieces of dead telemetry code found while root-causing the
docs pageview re-fire investigation (GROWTH-997, closed with no fix
needed). Pure deletion, 30 lines, no behavior change.

## Changes
- Delete `apps/www/app/ConsentWrapper.tsx`: an unwired third
`PageTelemetry` mount. www already mounts `PageTelemetry` in
`pages/_app.tsx` (Pages Router) and `app/providers.tsx` (App Router);
nothing imports this wrapper.
- Remove the exported `POSTHOG_URL` constant from
`apps/studio/lib/constants/index.ts`: zero consumers. The CSP allowlist
in `apps/studio/csp.ts` defines and uses its own local `POSTHOG_URL`,
which stays.

## Testing
Deadness verified before deletion, on current master:
- [x] Repo-wide grep for `ConsentWrapper`: only self-references inside
the deleted file
- [x] Repo-wide grep for `POSTHOG_URL`: remaining references are the
`csp.ts` local const only

## Linear
- fixes GROWTH-1002


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Bug Fixes**
* Removed an obsolete consent-related page wrapper to streamline page
behavior.
* Updated application configuration handling without changing existing
payment or usage settings.

* **Refactor**
* Simplified internal configuration and page composition while
preserving the existing user experience.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

apps/studio/lib/constants/index.ts

@@ -59,12 +59,6 @@ export const GOTRUE_ERRORS = {
 export const STRIPE_PUBLIC_KEY =
   process.env.NEXT_PUBLIC_STRIPE_PUBLIC_KEY || 'pk_test_XVwg5IZH3I9Gti98hZw6KRzd00v5858heG'
 
-export const POSTHOG_URL =
-  process.env.NEXT_PUBLIC_ENVIRONMENT === 'staging' ||
-  process.env.NEXT_PUBLIC_ENVIRONMENT === 'local'
-    ? 'https://ph.supabase.green'
-    : 'https://ph.supabase.com'
-
 export const USAGE_APPROACHING_THRESHOLD = 0.75
 
 export const DOCS_URL = process.env.NEXT_PUBLIC_DOCS_URL || 'https://supabase.com/docs'

apps/www/app/ConsentWrapper.tsx

@@ -1,24 +0,0 @@
-'use client'
-
-import { IS_PLATFORM, PageTelemetry } from 'common'
-import { useConsentToast } from 'ui-patterns/consent'
-import { API_URL } from '~/lib/constants'
-
-interface ConsentWrapperProps {
-  children: React.ReactNode
-}
-
-export function ConsentWrapper({ children }: ConsentWrapperProps) {
-  const { hasAcceptedConsent } = useConsentToast()
-
-  return (
-    <>
-      {children}
-      <PageTelemetry
-        API_URL={API_URL}
-        hasAcceptedConsent={hasAcceptedConsent}
-        enabled={IS_PLATFORM}
-      />
-    </>
-  )
-}