[FIX] Orange restart dialogs: Improve wording

[JakaKokosar]

Issue

Fixes #2581

Description of changes

Reset widget settings:

Also for add-on manager:

Includes

• Code changes
• Tests
• Documentation

[lanzagar]

Maybe:
A restart of the application is necessary -> Orange needs to be restarted
?

We are also somewhat misleading here by letting the user select "restart" and then stare at the computer when orange closes and does not start again :)
But I am fine with this if it is hard to actually restart the application (we would need to close the current one to save settings etc, before starting a new instance).

Also, note that pylint is complaining - it seems you removed a call to a function that is now imported, but never used.

[codecov]

Codecov Report

Merging #3605 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3605      +/-   ##
==========================================
- Coverage   84.02%   84.01%   -0.01%     
==========================================
  Files         370      370              
  Lines       67232    67232              
==========================================
- Hits        56490    56486       -4     
- Misses      10742    10746       +4

[JakaKokosar]

@lanzagar, is this clearer?

Reset widget settings: "Close Orange or cancel operation"

add-on manager: "Close Orange or do it later (operation was already performed)"

[lanzagar]

I think the second part of the message was good before ("for the changes to take effect") since it indicates what will happen if the user clicks Cancel (-> then changes will not take effect).
I would also add "now" at the end of "press ok to close orange"

In summary, the whole message should be:

Orange needs to be restarted for the changes to take effect.
Press OK to close Orange now.