test: test under ESLint v10

[bmish]

Fixes #655.

Title: chore: add ESLint 10 CI testing and remove deprecated type from test errors

Summary

• Removed the type property from RuleTester error objects across 21 test files (168 instances). ESLint 10 throws if type is present in invalid test case errors. This is backward-compatible with ESLint 8/9 since type was always optional.
• Added a CI step to run unit tests against ESLint 10 on Node 20.x, following the same pattern used historically when adding ESLint 8 support.
• Bumped @typescript-eslint/parser to 8.54.0 for ESLint 10 compatibility (ScopeManager#addGlobals).

Test plan

• All 1353 tests pass on both ESLint 9 and ESLint 10.

[coveralls]

Pull Request Test Coverage Report for Build 21776073094

Details

• 5 of 5 (100.0%) changed or added relevant lines in 5 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.008%) to 92.026%

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Totals
Change from base Build 21775849975:	0.008%
Covered Lines:	998
Relevant Lines:	1072

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💛 - Coveralls