realm_export: Add support to create full data export via /export/realm.

Earlier, only public data export was possible via `POST /export/realm`
endpoint. This commit adds support to create full data export with
member consent via that endpoint.

Also, this adds a 'export_type' parameter to the dictionaries
in `realm_export` event type and `GET /export/realm` response.

Fixes part of #31201.

web/src/settings_exports.ts

@@ -23,6 +23,7 @@ const realm_export_schema = z.object({
     deleted_timestamp: z.number().nullable(),
     failed_timestamp: z.number().nullable(),
     pending: z.boolean(),
+    export_type: z.number(),
 });
 type RealmExport = z.output<typeof realm_export_schema>;