Throwing warning if frameworks get imported on importing ivy (#11784)

Co-authored-by: Ved Patwardhan <[email protected]>

ivy/__init__.py

@@ -1155,3 +1155,12 @@ def __exit__(self, type, value, traceback):
 
 def dynamic_backend_as(value):
     return DynamicBackendContext(value)
+
+
+modules = ivy.utils.backend.handler._backend_dict.keys()
+for module in modules:
+    if module != "numpy" and module in sys.modules:
+        warnings.warn(
+            f"{module} module has been imported while ivy doesn't import it without "
+            "setting a backend, ignore if that's intended"
+        )