Editing filter does not update the stream

[thespacedoctor]

This is not necessarily a bug but confusing.

When I create a new filter the associated stream is generated. However, when I edit the filter the stream remains untouched and transients matching the newly edited stream are appended to the old stream as time goes on. I think it would be better to completely wipe the stream and start again so that filter and associated stream are equivalent.

When trying to bypass this niggle I tried deleting my filter and recreate it hoping the stream would also be trashed. This was not the case as the stream again remained untouched. It would be better if when deleting a filter the associated stream is also immediately trashed.

For example I have deleted the 'TDE-candidates v3.0' filter but the stream seems to still exist:

https://lasair.roe.ac.uk/streamdigest/13TDE-candidatesv3.0/