Allow "Remove subsequence" and "Replace subsequence" features and junction point in circular sequence

It is easy to select a region that includes a junction point in the Circular View. Such region is represented in UGENE as a joined region "join(reg_begin..seq_end,1..reg_end)".
"Replace subsequence" and "Remove subsequence" dialogs do not allow one to input such region.

Allow these dialogs to work with regions, that consist of two parts conjunct into one logical region by the junction point.

Note that there is no need to allow to work with any joined regions, improve only for regions that can be reinterpreted as a single region.