Adding a custom MAAS sstreams image source without trailing / fails

[Jeff Hillman]

Focal
MAAS 3.2.9

When editing the source to download MAAS images, and putting an the proper URL (https://some.domain.com) without a trailing "/" will cause MAAS to error saying it has hit max retries for that connection.

Specifically, it isn't realizing that there is no trailing slace and instead mangles the URL to be https://some.domain.comstreams/v1 which obviously fails.

Expected behavior would be for there to be some kind of handlnig to see if the trailing / is present and if not, add it.