fix(mimic)!: Remove libtest2-harness from public API

[epage]

Planning to reduce the amount of policy in libtest2-harness and realized we should just decouple these packages.

[coveralls]

Pull Request Test Coverage Report for Build 17624797194

Details

• 0 of 61 (0.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.5%) to 31.404%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
crates/libtest2-harness/src/harness.rs	0	30	0.0%
crates/libtest2-mimic/src/lib.rs	0	31	0.0%

Totals
Change from base Build 17504411795:	-0.5%
Covered Lines:	483
Relevant Lines:	1538

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💛 - Coveralls