[MM-38239 & MM-39788] Recent files causing crash (#18942)

* wip

* adding tests for new endpoint

* tool updates

* new function for getting postsByIds

* fixing test

* adding limit of 1000 to post query

* fixing PR comments

* fixing permission logic

Co-authored-by: Collin <collineng@gmail.com>
Co-authored-by: Collin Eng <eng.engineereng@gmail.com>
Co-authored-by: Benjamin Cooke <benjamincooke@Benjamins-MacBook-Pro.local>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Benjamin Cooke <benjamincooke@Benjamins-MBP.ht.home>

i18n/en.json

@@ -2215,6 +2215,10 @@
     "id": "api.post.patch_post.can_not_update_post_in_deleted.error",
     "translation": "Can not update a post in a deleted channel."
   },
+  {
+    "id": "api.post.posts_by_ids.invalid_body.request_error",
+    "translation": "The number of Post IDs received has exceeded the maximum size of {{.MaxLength}}"
+  },
   {
     "id": "api.post.search_files.invalid_body.app_error",
     "translation": "Unable to parse the request body."