Refactor: fixup usage of contextlib.suppress()

[ulidtko]

Followup fixup to #639.

Checklist

• I've ensured that similar functionality has not already been implemented
• I've ensured that similar functionality has not earlier been proposed and declined
• I've branched off the master or python-dual-support branch
• I've merged fresh upstream into my branch recently
• I've ran tox successfully in local environment
• I've included docstrings and/or documentation and/or examples for my code (if this is a new feature)

[coveralls]

Pull Request Test Coverage Report for Build 6323870897

• 16 of 20 (80.0%) changed or added relevant lines in 7 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 74.386%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
urwid/canvas.py	4	5	80.0%
urwid/vterm.py	2	3	66.67%
urwid/util.py	1	3	33.33%

Totals
Change from base Build 6323654563:	0.0%
Covered Lines:	7518
Relevant Lines:	10290

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💛 - Coveralls

[penguinolog]

Historically I was almost always used OpenStack style of imports (import packages, not objects), but technically current PR should make code a bit more efficient