Let user select if the ID is in field "id" or "fid"

[rekjuh]

Expected behaviour
The plugin has an option where the user can define the name of the ID field. Probably the most likely names for ID are "id" and "fid", so this can be a tick-box option. Or then a free text box for special cases?

Current behaviour
The plugin works only if the layer has features with ID column "fid". If the ID column is called e.g. "id", the plugin gives an error.

Describe alternatives you've considered
The user changes the name of the ID field to "fid" or creates a new ID column called "fid".

Additional context