The Select Similar UV operator defined multiple enum item arrays, and
returned one depending on current mode in the enum function
uv_select_similar_type_itemf().
The operator prop's enum items used only the vertex items, which
resulted in several items never being extracted because they were
dynamically generated instead of exposed to the RNA.
This commit groups all items in a single array so that they are
exposed, but uses the enum function to filter them.
Issue reported by Satoshi Yamasaki (@SatoshiYamasaki) in #43295.
Damien Picard