feat(connections): add an onDisconnect lifecycle hook to connection providers (#23538)

Platform half of the follow-up to
https://github.com/twentyhq/twenty/pull/22984#discussion_r3673946334.
The Slack app claims a `team_id` on connect and had no way to release
it, because connection providers only had an on-connect hook. Nothing
here is Slack-specific, so it targets `main`. The app side is #23540, on
top of `feat/slack-bot`, and waits on this plus an SDK release.

## What changes

`defineConnectionProvider` accepts `onDisconnectLogicFunction` alongside
`onConnectLogicFunction`. It is stored on
`connectionProvider.onDisconnectLogicFunctionUniversalIdentifier` (fast
instance command `2.26.0_...1785350000000`) and enqueued right after the
`ConnectedAccount` row is deleted, in the disconnecting workspace, with
the same payload as on-connect:

```ts
type OnDisconnectPayload = {
  connectionProviderId: string;
  connectionProviderName: string;
  connectedAccountId: string;
};
```

The `ConnectedAccount` is gone by the time the hook runs, so
`getConnection` no longer resolves. Anything the cleanup needs has to be
in the key-value store, written at connect time and keyed by
`connectedAccountId`. The docs section spells that out, along with the
fact that uninstalling an app drops its connections through a cascade
that never reaches this hook, where `uninstallLogicFunction` is the
right tool instead.

Both dispatches moved into a new
`ConnectionProviderLifecycleHookService`, so
`ConnectionProviderOAuthFlowService` no longer owns hook plumbing and
`ConnectedAccountMetadataService.delete` can reuse it. On-connect
behaviour is unchanged: best effort, never blocks the caller, failures
go to Sentry.

## Tests

- `connection-provider-lifecycle-hook.service.spec.ts`: the on-connect
cases moved over, plus on-disconnect dispatch, no-hook, and
missing-provider cases
- `connection-provider-oauth-flow.service.spec.ts`: now asserts
delegation to the lifecycle hook service
- SDK validation, manifest duplicate-identifier, and manifest to flat
converter specs extended

Server unit tests and typecheck for shared, sdk and server pass locally.

packages/twenty-shared/src/application/connectionProviderManifestType.ts

@@ -7,4 +7,5 @@ export type ConnectionProviderManifest = SyncableEntityOptions & {
   type: 'oauth';
   oauth: OAuthConnectionProviderConfig;
   onConnectLogicFunction?: SyncableEntityOptions;
+  onDisconnectLogicFunction?: SyncableEntityOptions;
 };