Generate distance matrix: GUI improvements

1. Open "_common_data/scenarios/msa/ma2_gapped.aln".
2. MSA area context menu -> Statistics -> Generate distance matrix.
Fix it: a) add "..." after the both actions because they leads to new dialogs.
Expected: the dialog appears.
Fix it: b) "Percents" -> "Percent". There is no the word "Percents" in English.
3. Check "Save profile to file".
Fix it: c) Add the default file path.
4. Click generate.
Fix it: d) Nothing happens. Add the task report with the clickable output file url.
5. Repeat 2 and 4 (without 3).
Expected: the matrix MDI appears.
Fix it: e) Add paddings for the table cells. Now the borders touch the text inside of cells.
Fix it: f) It is possible to call a context menu. Block it.