warning/error log messages should not contain ANSI escape sequences

[tonycpsu]

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Description of your issue, suggested solution and other information

I am developing a console application using urwid. When youtube_dl reports errors, even with ignoreerrors=True, I'm getting output to the console, which interferes with the operation of my app.

I see in the comments to #9281 that "Logger can be used to intercept errors though it will hook all the errors not only ExtractorError." Doing this does, in fact, get the errors passed to my application's log handler, but it does so with unsightly ANSI escape codes in it:

My proposed solution would be to not add the WARNING/ERROR strings (and certainly not the color codes) if the user passes in their own logger.

[dstftw]

--no-color.