Report: Fix saving to PDF

[janezd]

Issue

In Qt6, QPrinter no longer contains an enum with page sizes, e.g. QPrinter.A4. I haven't found a notice that enum is obsolete and removed, but I found this.

To reproduce, on macOS:

• Report something
• Click Print
• Choose PDF -> Save as PDF ...
• Enter file name, click Save

Crashes with

File "/Applications/Orange.app/Contents/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/orangewidget/report/owreport.py", line 350, in save_report
    printer.setPageSize(QPrinter.A4)
                        ^^^^^^^^^^^
AttributeError: type object 'QPrinter' has no attribute 'A4'

Description of changes

Use QPageSize.

Includes

• Code changes

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.03%. Comparing base (05bbef6) to head (39b8e9a).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #281      +/-   ##
==========================================
+ Coverage   71.76%   72.03%   +0.26%     
==========================================
  Files          34       34              
  Lines        9117     9117              
==========================================
+ Hits         6543     6567      +24     
+ Misses       2574     2550      -24     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.