[FIX] Update check and notifications: avoid compression

[markotoplak]

Issue

Update check failed for me because the response was compresses, and urllib (if I understand it) does not decompress it automatically.

2025-06-02 13:30:08,020:ERROR:Orange.canvas.__main__: Failed to check for updates Traceback (most recent call last):
  File "/home/marko/dev/orange3/Orange/canvas/__main__.py", line 97, in run
    contents = urlopen(request, timeout=10).read().decode()

Description of changes

Force identity encoding.

Includes

• Code changes
• Tests
• Documentation

[markotoplak]

There is other place in orange3 code base where we could get a similar problem: in UrlReader. Does anyone remember any problems with it?

Here, I think we had a bug because we even requested a gzip, and the server happily started obliging. But I am not sure what is the default value of 'Accept-Encoding' in urllib and how is that handled on servers.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (master@66928eb). Learn more about missing BASE report.
⚠️ Report is 96 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #7097   +/-   ##
=========================================
  Coverage          ?   88.71%           
=========================================
  Files             ?      332           
  Lines             ?    73396           
  Branches          ?        0           
=========================================
  Hits              ?    65114           
  Misses            ?     8282           
  Partials          ?        0           

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[markotoplak]

If this was the problem, users will not be notified of a new version.

@lanzagar suggested setting the server not to compress, if this is possible (this goes through Cloudflare).