test: improve error tests

[pd4d10]

Prerequisites of #392 , to make sure the styles are correct.

Before #156 (comment) gets confirmed, use hard code instead.

[codecov]

Codecov Report

Merging #407 (7b05f3b) into main (2eb7155) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #407   +/-   ##
=======================================
  Coverage   59.71%   59.71%           
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  Files          56       56           
  Lines        3664     3664           
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  Hits         2188     2188           
  Misses       1476     1476           

Impacted Files	Coverage Δ
crates/cli/src/error.rs	45.31% <ø> (ø)

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[HerringtonDarkholme]

Thank you for the contribution!
However I would like to change the test case a little more.

First, the test case itself is not readable. I have not decided to use which format for colorization test.

Second, the test is for UI. We will probably change it in future so test might be frequently broken.

I would rather test if a colorized string appears in the error message.