[spreadsheet] when generating values via a function, allow to control

Description

When generating values via a function, allow to control whether the target spreadsheet should be resized to the size of the variable columns. This is helpful for example if the source/variable has more values than the target column in another spreadsheet and its size shouldn't be changed (only the first N-values of the function are of an interest).

P.S.: this MR was triggered by the discussion in https://bugs.kde.org/show_bug.cgi?id=474732 but is not addressing it (or only for some of the cases) - this problem will need to be solved differently, current proposal for it is !373 (merged).

Conformity

• Changelog entry
• Downport
• Unittests
• Fixes:

If external dependencies are removed

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