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

@@ -434,6 +434,17 @@ async def update_agent(
 ) -> Response:
     user: KhojUser = request.user.object
 
+    selected_agent = await AgentAdapters.aget_agent_by_slug(body.slug, user)
+
+    if not selected_agent:
+        return Response(
+            content=json.dumps({"error": f"Agent with name {body.name} not found."}),
+            media_type="application/json",
+            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
         )
@@ -445,15 +456,6 @@ async def update_agent(
                 status_code=400,
             )
 
-    selected_agent = await AgentAdapters.aget_agent_by_slug(body.slug, user)
-
-    if not selected_agent:
-        return Response(
-            content=json.dumps({"error": f"Agent with name {body.name} not found."}),
-            media_type="application/json",
-            status_code=404,
-        )
-
     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: