Pipeend useful tickets

Useful tickets for reference

Below is a list of useful tickets which were not worked on but which should be reviewed if further work is done on pipeends.

1. #3342 - Changing channel direction has bad UI
2. #3559 - Pipe-ends overview ticket 2022-09
3. #3407 - Pipe-end detach from channel doesn't work
4. #5671 - junction.invert_level not syncing with pipeend.invert_depth (CLOSED)
5. #3406 - Changing a channel updates a connected pipe-end's letter wrong
6. #3322 - Issues around pipe-end detach and delete
7. #3405 - Detached pipe-end's length still reflects previous channel
8. #3343 - It is very easy to convert a channel to a point channel which is basically lost
9. #3410 - to clarify: pipeend.stream_posn