Python: Add self.request as RemoteFlowSource for aiohttp View

Just like we do for Django in
7393443f8c/python/ql/src/semmle/python/frameworks/Django.qll (L1786-L1804)

python/ql/test/library-tests/frameworks/aiohttp/taint_test.py

@@ -196,7 +196,8 @@ async def test_taint(request: web.Request): # $ requestHandler
 class TaintTestClass(web.View):
     def get(self): # $ requestHandler
         ensure_tainted(
-            self.request, # $ MISSING: tainted
+            self.request, # $ tainted
+            self.request.url # $ tainted
         )