Error when unauthorized user attempts to Edit someone else's backblast

[jermo5]

When "Lock editing of backblasts?" is set to "Yes" and an unauthorized person (not an admin/q/poster) clicks "Edit this backblast" button, the following error is thrown: "argument of type 'NoneType' is not iterable.

It could possibly be in the following function: https://github.com/F3Nation-Community/slackblast/blob/48a33e138adc0278c2cbb015b616617424dfcc54/slackblast/features/backblast.py#L635

Link to Slack thread discussion on this error: https://f3nation.slack.com/archives/C01HCL3VBEG/p1719857290995339?thread_ts=1712258604.289599&cid=C01HCL3VBEG