General fix to Lexicon Edit Popup problems

[jtmaxwell3]

This is a general fix to problems with the Lexicon Edit Popup window, of which https://jira.sil.org/browse/LT-22352 is one instance (see in particular Bharanidharan's comment). The general problem is that the Lexicon Edit Popup window often violates the assumptions in the context menu commands and cause them to crash. In particular, there is an assumption that the Lexicon Edit pane is in the Lexicon frame and there are no other edit windows active at the same time. There are too many context menu commands in the Lexicon Edit pane to try to fix them all. So I disabled all of them. If the user tries to use a context menu, they get the error "Context menus are disabled in popup windows.".

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This change is 

[jtmaxwell3]

BTW, Bharanidharan's error was the result of refreshing the interlinear text after senses were merged and the interlinear text having a reference to the sense that was deleted by the merge.

[jasonleenaylor]

@jasonleenaylor reviewed 8 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @jtmaxwell3).

[jasonleenaylor]

I'm approving this for now (to stave off the crashes) but I would rather see the menu items disabled.

@jasonleenaylor made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved.