[flake8-use-pathlib] Delete unused Rule::OsSymlink enabled check (#20099)

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## Summary
Part of #20009 (i forgot to delete it in this PR)
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## Test Plan

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crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -1046,7 +1046,6 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 Rule::PyPath,
                 Rule::Glob,
                 Rule::OsListdir,
-                Rule::OsSymlink,
             ]) {
                 flake8_use_pathlib::rules::replaceable_by_pathlib(checker, call);
             }