fix(logic-function): forward raw request body for HMAC signature verification (#20061)

## Summary

- Add optional `rawBody?: string` to `LogicFunctionEvent` and forward it
from the route trigger so HMAC-based webhook signatures (GitHub's
`X-Hub-Signature-256`, Stripe, …) can be verified by user logic
functions.
- Update `github-connector`'s `getRawBodyForSignature` to prefer
`event.rawBody` (with the existing string/base64/null fallbacks kept for
older runtimes).

## Why

GitHub computes `X-Hub-Signature-256` over the **raw bytes** of the
request body. The receiver must verify against those exact bytes — key
order, whitespace and unicode escaping all matter, so the parsed JSON
body cannot be re-serialized to them.

Today the route trigger calls `extractBody(request)` which returns the
parsed object only. NestJS already preserves the raw body on
`request.rawBody` (the app is bootstrapped with `rawBody: true` in
`main.ts`), but it was never propagated into `LogicFunctionEvent`.

As a result the github-connector's webhook handler always took the "raw
body unavailable" branch and rejected every delivery (after #19961 /
962c2b3c14). With this change, signature verification can succeed
end-to-end.

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/twenty-apps/community/github-connector/src/modules/github/connector/webhook-signature.ts

@@ -7,7 +7,11 @@ export type SignatureVerificationResult =
 export function getRawBodyForSignature(event: {
   body: unknown;
   isBase64Encoded?: boolean;
+  rawBody?: string;
 }): string | null {
+  if (typeof event.rawBody === 'string') {
+    return event.rawBody;
+  }
   const raw = event.body;
   if (raw == null) return '';
   if (typeof raw === 'string') {