Set $NODE_ENV according to the image purpose during Docker build (#1088)

* Set $NODE_ENV according to the image purpose during Docker build

* Move `husky` from dev-deps to prod-deps, as it is used during prod `npm ci`

---------

Co-authored-by: Konstantin Koval <kkb@ukr.net>

.github/workflows/tests.yml

@@ -105,6 +105,8 @@ jobs:
         tags: photoview/ui
         cache-from: type=gha
         cache-to: type=gha,mode=max
+        build-args: |
+          NODE_ENV=testing
 
     - name: Test
       id: test