chore: Removing disabling functionality for cross site embedding (#40167)

## Description

Removing disabling functionality for cross site embedding

Fixes #`Issue Number`  
_or_  
Fixes `Issue URL`
> [!WARNING]  
> _If no issue exists, please create an issue first, and check with the
maintainers if the issue is valid._

## Automation

/ok-to-test tags="@tag.Settings"

### 🔍 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/14333026511>
> Commit: 44f04a277fa98caf04775f3fc890600749f16248
> <a
href="https://internal.appsmith.com/app/cypress-dashboard/rundetails-65890b3c81d7400d08fa9ee5?branch=master&workflowId=14333026511&attempt=1"
target="_blank">Cypress dashboard</a>.
> Tags: `@tag.Settings`
> Spec:
> <hr>Tue, 08 Apr 2025 12:28:31 UTC
<!-- end of auto-generated comment: Cypress test results  -->


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


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

## Summary by CodeRabbit

- **Refactor**
- Removed the cross-site embedding setting from Admin Settings,
streamlining configuration management while maintaining existing
functionality for administrators.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

app/client/src/ce/pages/AdminSettings/config/configuration.tsx

@@ -59,19 +59,6 @@ export const APPSMITH_POOL_SIZE_CONFIG: Setting = {
   isVisible: () => !isAirgappedInstance,
 };
 
-export const APPSMITH_IS_CROSS_SITE_EMBEDDING_ENABLED: Setting = {
-  id: "isCrossSiteEmbeddingEnabled",
-  name: "isCrossSiteEmbeddingEnabled",
-  category: SettingCategories.CONFIGURATION,
-  controlType: SettingTypes.CHECKBOX,
-  label: "Private embeds",
-  text: "Enable embedding of private Appsmith apps on external domains beyond the current domain",
-  tooltip:
-    "Users will need to log out and log in again to be able to use embeds across domains",
-  isFeatureEnabled: false,
-  isDisabled: () => true,
-};
-
 export const APPSMITH_ALLOWED_FRAME_ANCESTORS_SETTING: Setting = {
   id: "APPSMITH_ALLOWED_FRAME_ANCESTORS",
   name: "APPSMITH_ALLOWED_FRAME_ANCESTORS",
@@ -150,7 +137,6 @@ export const config: AdminConfigType = {
     APPSMITH_DB_URL,
     APPSMITH_REDIS_URL,
     APPSMITH_POOL_SIZE_CONFIG,
-    APPSMITH_IS_CROSS_SITE_EMBEDDING_ENABLED,
     APPSMITH_ALLOWED_FRAME_ANCESTORS_SETTING,
   ],
 };