chore: rename npm goal "watch" to "watch-build" to avoid ambiguity as now we also have "watch-test"

Note: this change might break existing scripts if they use "watch" goal. But I assume that there no
such scripts.

Author: php-coder

src/main/frontend/package.json

@@ -23,7 +23,7 @@
   },
   "scripts": {
     "build": "webpack",
-    "watch": "webpack --watch",
+    "watch-build": "webpack --watch",
     "test": "jest",
     "watch-test": "jest --watch"
   },