Run safety check only when agent persona updated on agent edits

Running safety check isn't required if the agent persona wasn't
updated this time around as it would have passed safety check
previously.

This should speed up editing agents when agent persona isn't updated.

src/khoj/routers/api_agents.py

@@ -434,17 +434,6 @@ async def update_agent(
 ) -> Response:
     user: KhojUser = request.user.object
 
-    is_safe_prompt, reason = await acheck_if_safe_prompt(
-        body.persona, user, lax=body.privacy_level == Agent.PrivacyLevel.PRIVATE
-    )
-
-    if not is_safe_prompt:
-        return Response(
-            content=json.dumps({"error": f"{reason}"}),
-            media_type="application/json",
-            status_code=400,
-        )
-
     selected_agent = await AgentAdapters.aget_agent_by_slug(body.slug, user)
 
     if not selected_agent:
@@ -454,6 +443,19 @@ async def update_agent(
             status_code=404,
         )
 
+    if selected_agent.personality != body.persona:
+        # Check if the new persona is safe
+        is_safe_prompt, reason = await acheck_if_safe_prompt(
+            body.persona, user, lax=body.privacy_level == Agent.PrivacyLevel.PRIVATE
+        )
+
+        if not is_safe_prompt:
+            return Response(
+                content=json.dumps({"error": f"{reason}"}),
+                media_type="application/json",
+                status_code=400,
+            )
+
     subscribed = has_required_scope(request, ["premium"])
     chat_model = await ConversationAdapters.aget_chat_model_by_friendly_name(body.chat_model)
     if subscribed or chat_model.price_tier == PriceTier.FREE: