chore: Remove unused JSON superuser signup route (appsmithorg#37378)

The JSON payload version of the super user signup route is not used
anywhere significant. This PR removes it.


## Automation

/test sanity authentication

### 🔍 Cypress test results
<!-- This is an auto-generated comment: Cypress test results  -->
> [!TIP]
> 🟢 🟢 🟢 All cypress tests have passed! 🎉 🎉 🎉
> Workflow run:
<https://github.com/appsmithorg/appsmith/actions/runs/11830003644>
> Commit: d051ed8
> <a
href="https://internal.appsmith.com/app/cypress-dashboard/rundetails-65890b3c81d7400d08fa9ee5?branch=master&workflowId=11830003644&attempt=1"
target="_blank">Cypress dashboard</a>.
> Tags: `@tag.Sanity, @tag.Authentication`
> Spec:
> <hr>Thu, 14 Nov 2024 03:53:00 UTC
<!-- end of auto-generated comment: Cypress test results  -->


## Communication
Should the DevRel and Marketing teams inform users about this change?
- [ ] Yes
- [x] No


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Updated user creation process to use URL-encoded data instead of JSON
for super user creation.
  
- **Bug Fixes**
- Removed deprecated `createSuperUser` methods from the API and server
controllers, streamlining user management.

- **Chores**
- Modified setup scripts to reflect changes in user data transmission
for creating super users.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

appsmith-server/src/main/java/com/appsmith/server/controllers/ce/UserControllerCE.java

@@ -9,7 +9,6 @@
 import com.appsmith.server.dtos.ResetUserPasswordDTO;
 import com.appsmith.server.dtos.ResponseDTO;
 import com.appsmith.server.dtos.UserProfileDTO;
-import com.appsmith.server.dtos.UserSignupRequestDTO;
 import com.appsmith.server.dtos.UserUpdateDTO;
 import com.appsmith.server.services.SessionUserService;
 import com.appsmith.server.services.UserDataService;
@@ -70,19 +69,6 @@ public Mono<Void> createFormEncoded(ServerWebExchange exchange) {
         return userSignup.signupAndLoginFromFormData(exchange);
     }
 
-    @JsonView(Views.Public.class)
-    @PostMapping(
-            value = "/super",
-            consumes = {MediaType.APPLICATION_JSON_VALUE})
-    public Mono<ResponseDTO<User>> createSuperUser(
-            @Valid @RequestBody UserSignupRequestDTO resource,
-            @RequestHeader("Origin") String originHeader,
-            ServerWebExchange exchange) {
-        return userSignup
-                .signupAndLoginSuper(resource, originHeader, exchange)
-                .map(created -> new ResponseDTO<>(HttpStatus.CREATED.value(), created, null));
-    }
-
     @JsonView(Views.Public.class)
     @PostMapping(
             value = "/super",