Avoid triggering single-element test for starred expressions (#8433)

See:
#8402 (comment)

crates/ruff_linter/resources/test/fixtures/refurb/FURB171.py

@@ -43,3 +43,6 @@
 
 if "a" == "a":
     pass
+
+if 1 in {*[1]}:
+    pass

crates/ruff_linter/src/rules/refurb/rules/single_item_membership_test.rs

@@ -1,8 +1,7 @@
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::generate_comparison;
-use ruff_python_ast::ExprStringLiteral;
-use ruff_python_ast::{CmpOp, Expr};
+use ruff_python_ast::{self as ast, CmpOp, Expr, ExprStringLiteral};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -95,13 +94,17 @@ pub(crate) fn single_item_membership_test(
     checker.diagnostics.push(diagnostic);
 }
 
-/// Return the single item wrapped in Some if the expression contains a single
-/// item, otherwise return None.
+/// Return the single item wrapped in `Some` if the expression contains a single
+/// item, otherwise return `None`.
 fn single_item(expr: &Expr) -> Option<&Expr> {
     match expr {
-        Expr::List(list) if list.elts.len() == 1 => Some(&list.elts[0]),
-        Expr::Tuple(tuple) if tuple.elts.len() == 1 => Some(&tuple.elts[0]),
-        Expr::Set(set) if set.elts.len() == 1 => Some(&set.elts[0]),
+        Expr::List(ast::ExprList { elts, .. })
+        | Expr::Tuple(ast::ExprTuple { elts, .. })
+        | Expr::Set(ast::ExprSet { elts, .. }) => match elts.as_slice() {
+            [Expr::Starred(_)] => None,
+            [item] => Some(item),
+            _ => None,
+        },
         string_expr @ Expr::StringLiteral(ExprStringLiteral { value: string, .. })
             if string.chars().count() == 1 =>
         {