[real-time] Promisify DocumentUpdaterManager (#30322)

* move function outside of object

* convert flushProjectToMongoAndDelete function

* convert queueChange function

* install fetch utils, remove private fn from export

* promisify getDocument function

* fix unit tests

* preserve function order

* try parsing error body

* update tests on a new rebased file

* remove fetch-utils from devDependencies

GitOrigin-RevId: cc34d6f690b6b888214b32c2aee0efb6b585e159

services/real-time/package.json

@@ -18,6 +18,7 @@
     "types:check": "tsc --noEmit"
   },
   "dependencies": {
+    "@overleaf/fetch-utils": "*",
     "@overleaf/logger": "*",
     "@overleaf/metrics": "*",
     "@overleaf/o-error": "*",
@@ -40,7 +41,6 @@
     "zod-validation-error": "^4.0.1"
   },
   "devDependencies": {
-    "@overleaf/fetch-utils": "*",
     "chai": "^4.3.6",
     "chai-as-promised": "^7.1.1",
     "cookie-signature": "^1.1.0",