chore: Remove function calling flag (#39790)

## Description
> [!TIP]  
> _Add a TL;DR when the description is longer than 500 words or
extremely technical (helps the content, marketing, and DevRel team)._
>
> _Please also include relevant motivation and context. List any
dependencies that are required for this change. Add links to Notion,
Figma or any other documents that might be relevant to the PR._


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=""

### 🔍 Cypress test results
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> [!CAUTION]  
> If you modify the content in this section, you are likely to disrupt
the CI result for your PR.

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## 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

- **Refactor**
- Updated the logic that determines when the visualization view is
enabled, now relying on a refined integration check.
  
- **Chores**
- Removed an outdated configuration toggle from overall feature
settings.
  - Streamlined override options by eliminating an unnecessary flag.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

app/client/src/ce/entities/FeatureFlag.ts

@@ -53,7 +53,6 @@ export const FEATURE_FLAG = {
     "release_external_saas_plugins_enabled",
   release_tablev2_infinitescroll_enabled:
     "release_tablev2_infinitescroll_enabled",
-  release_fn_calling_enabled: "release_fn_calling_enabled",
 } as const;
 
 export type FeatureFlag = keyof typeof FEATURE_FLAG;
@@ -98,7 +97,6 @@ export const DEFAULT_FEATURE_FLAG_VALUE: FeatureFlags = {
   release_ads_entity_item_enabled: false,
   release_external_saas_plugins_enabled: false,
   release_tablev2_infinitescroll_enabled: false,
-  release_fn_calling_enabled: false,
 };
 
 export const AB_TESTING_EVENT_KEYS = {

app/client/src/components/editorComponents/JSResponseView.tsx

@@ -42,7 +42,7 @@ import { StateInspector } from "./Debugger/StateInspector";
 import { getErrorCount } from "selectors/debuggerSelectors";
 import { getIDETypeByUrl } from "ee/entities/IDE/utils";
 import { useLocation } from "react-router";
-import { getReleaseFnCallingEnabled } from "layoutSystems/anvil/integrations/selectors";
+import { getIsAnvilEnabledInCurrentApplication } from "layoutSystems/anvil/integrations/selectors";
 import { Visualization } from "PluginActionEditor/components/PluginActionResponse/components/Visualization";
 
 const ResponseTabWrapper = styled.div`
@@ -214,7 +214,7 @@ function JSResponseView(props: Props) {
 
   const ideViewMode = useSelector(getIDEViewMode);
   const location = useLocation();
-  const isFnCallingEnabled = useSelector(getReleaseFnCallingEnabled);
+  const isAnvilEnabled = useSelector(getIsAnvilEnabledInCurrentApplication);
 
   const ideType = getIDETypeByUrl(location.pathname);
 
@@ -227,7 +227,7 @@ function JSResponseView(props: Props) {
       },
     ];
 
-    if (isFnCallingEnabled) {
+    if (isAnvilEnabled) {
       responseTabs.push({
         key: DEBUGGER_TAB_KEYS.VISUALIZATION_TAB,
         title: "AI Response Visualizer",

app/client/src/layoutSystems/anvil/integrations/selectors.ts

@@ -10,10 +10,6 @@ export const getIsAnvilLayoutEnabled = (state: AppState) => {
   return selectFeatureFlagCheck(state, FEATURE_FLAG.release_anvil_enabled);
 };
 
-export const getReleaseFnCallingEnabled = (state: AppState) => {
-  return selectFeatureFlagCheck(state, FEATURE_FLAG.release_fn_calling_enabled);
-};
-
 /**
  * A selector to verify if the current application is an Anvil application.
  * This is done by getting the layout system type of the current application (getLayoutSystemType)

app/client/src/utils/hooks/useFeatureFlagOverride.ts

@@ -15,7 +15,6 @@ import {
 export const AvailableFeaturesToOverride: FeatureFlag[] = [
   "release_anvil_enabled",
   "release_layout_conversion_enabled",
-  "release_fn_calling_enabled",
 ];
 export type OverriddenFeatureFlags = Partial<Record<FeatureFlag, boolean>>;