revert: restore original behavior for missing request body; revert test expectation to 200

Author: yixianOu

apisix/plugins/ai-request-rewrite.lua

@@ -194,7 +194,7 @@ function _M.access(conf, ctx)
 
     if not client_request_body then
         core.log.warn("missing request body")
-        return HTTP_BAD_REQUEST
+        return
     end
 
     -- Prepare request for LLM service

t/plugin/ai-request-rewrite2.t

@@ -276,7 +276,7 @@ passed
                 }
             )
 
-            if code == 400 then
+            if code == 200 then
                 ngx.say('passed')
                 return
             end

t/xrpc/pingpong.t

@@ -780,12 +780,14 @@ connect to 127.0.0.3:1995 while prereading client data
 connect to 127.0.0.1:1995 while prereading client data
 --- stream_conf_enable
 
+
+
 === TEST 22: cleanup
 --- config
     location /t {
         content_by_lua_block {
             local t = require("lib.test_admin").test
-            
+
             -- Delete dependent routes first
             local code, body = t('/apisix/admin/stream_routes/2', ngx.HTTP_DELETE)
             if code >= 300 then