[14.0][FIX] delivery_gls_asm: Convert into list if not Iterable
[14.0][FIX] delivery_gls_asm: Convert into list if not Iterable

- If the manifest only comes with 1 delivery it is in form of a singular dict instead of a list of dicts and this causes issues when iterating in the XML

cubells/l10n-spain,cubells/l10n-spain,cubells/l10n-spain