Testing PRs from within decky (#496)

* git no work so manually uploading files :(

* argh i wish git was working

* ok next time i'll make git work

* Update updater.py

* git please work next time this took ages without you

* fix me locales

* Update updater.py

* Update en-US.json

* Update updater.py

* Update updater.py

* i wish my python LSP stuff was working

* fix it

* Update updater.py

* Update updater.py

* Only show testing branch as an option if it is already selected

* Initial implementation for fetching the open PRs. Still need testing and a token to complete this.

* Wrong filter capitalization

* Fix a couple of typos in the python backend updater.

* Fix typos pt 3

* This should be the last one

* Prepend the PR version number with PR- to make it clearer that's the PR number.

* Update prettier to the latest version otherwise it will never be happy with the formatting.

* fix merge mistake

* fix pyright errors & type hint most new code

* fix strict pyright errors...

* not sure why my local linter didn't catch this

* Reimplement the logic between PR and artifact build to limit API calls

* Fix pyright errors

* use nightly.link for downloads

* remove accidental dollar sign

* fix various logical errors. the code actually works now.

* set branch to testing when user downloads a testing version

---------

Co-authored-by: Marco Rodolfi <marco.rodolfi@tuta.io>

backend/locales/en-US.json

@@ -192,7 +192,8 @@
   "SettingsIndex": {
     "developer_title": "Developer",
     "general_title": "General",
-    "plugins_title": "Plugins"
+    "plugins_title": "Plugins",
+    "testing_title": "Testing"
   },
   "Store": {
     "store_contrib": {
@@ -260,5 +261,8 @@
       "reloading": "Reloading",
       "updating": "Updating"
     }
-  }
+      },
+    "Testing": {
+        "download": "Download"
+    }
 }