Enable eslint rule 'no-case-declarations'

Enable recommended rule 'no-case-declarations' [1] and manually fix violations.

[1] https://eslint.org/docs/latest/rules/no-case-declarations

Ref: #8068
Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

eslint.config.mjs

@@ -28,6 +28,7 @@ const configEslintRecommended = {
 		"for-direction": "warn",
 		"getter-return": "warn",
 		"no-async-promise-executor": "warn",
+		"no-case-declarations": "warn",
 		"no-class-assign": "warn",
 		"no-compare-neg-zero": "warn",
 		"no-cond-assign": "warn",