revert json conversion

devops/aws/deploy-playground-playbook.yml

@@ -51,17 +51,12 @@
       # Check for the status every 100s
       delay: 100
 
-    - name: Format proposal parameters input
-      set_fact:
-        proposal_parameters_json: '{{ proposal_parameters | from_json | to_json }}'
-      run_once: yes
-
     - name: Build Node image
       command: yarn build:node:docker
       args:
         chdir: '{{ remote_code_path }}'
       environment:
-        ALL_PROPOSALS_PARAMETERS_JSON: '{{ proposal_parameters_json }}'
+        ALL_PROPOSALS_PARAMETERS_JSON: '{{ proposal_parameters }}'
       async: 3600
       poll: 0
       register: node_build_result