(maint) Fix publishing of metadata.json schema

Previously the metadata.json schema validation file was not being published.
This was due to it being in the src directory which is for typescript only. This
commit moves the file to a more appropriate schemas directory and updates the
package.json appropriately.

Author: glennsarti

client/package.json

@@ -69,7 +69,7 @@
     "jsonValidation": [
       {
         "fileMatch": "metadata.json",
-        "url": "./src/metadata-json-schema.json"
+        "url": "./schemas/metadata-json-schema.json"
       }
     ],
     "grammars": [