cli: tests: remove unneeded unicode conversion from TestEnvironment #6811

Job	Run time
nix flake (macos-14)	13m 31s
check (protos)	2m 1s
nix flake (ubuntu-24.04-arm)	6m 51s
check (rustfmt)	19s
check (doctests)	3m 7s
check (zizmor)	24s
check (clippy)	1m 28s
check (codespell)	10s
test (linux-x86_64-gnu)	6m 11s
test (linux-aarch64-gnu)	5m 43s
nix flake (ubuntu-24.04)	7m 46s
test (windows-x86_64)	14m 46s
test (macos-x86_64)	5m 27s
check (cargo-deny, advisories)	26s
check (mkdocs)	17s
check (cargo-deny, licenses)	26s
check (cargo-deny, bans)	28s
test (macos-aarch64)	10m 11s
check (latest mkdocs, optional)	7m 41s
test (windows-aarch64)	16m 30s
check (cargo-deny, sources)	27s
build (no git)	1m 29s
check (Cargo.lock dependency count)	5s
required checks (merge queue)	0s
	1h 45m 44s

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