fix(linter/unicorn/no-invalid-fetch-options): avoid treating unknown methods as GET (#28547)

Treat unresolved `method` identifier bindings as unknown instead of retaining the default `GET` method. This avoids false positives for contextually typed destructured parameters and unannotated parameters, matching `eslint-plugin-unicorn`.

Add six regression cases covering these bindings with both `fetch()` and `new Request()`. Existing diagnostics for known `GET` and `HEAD` methods remain unchanged.

Fixes #27772

crates/oxc_linter/src/rules/unicorn/no_invalid_fetch_options.rs

@@ -239,7 +239,9 @@ fn is_invalid_fetch_options<'a>(
                                 }
                             }
                         }
-                        _ => {}
+                        _ => {
+                            method_name = UNKNOWN_METHOD_NAME;
+                        }
                     }
                 }
                 _ => {
@@ -337,6 +339,14 @@ fn test() {
         (r#"new Request("/url", { method: (options).method, body: "some body" });"#),
         r#"enum M { A = "\uD800" } fetch(u, {method: M.A, body: "x"})"#,
         r#"enum M { A = "\uD800", B = "GET" } fetch(u, {method: M.A, body: "x"})"#,
+        r#"type Handler = (input: { body?: string; method: string }) => Promise<Response>;
+        export const contextual: Handler = ({ body, method }) => fetch("/", { body, method });"#,
+        r#"type Handler = (input: { body?: string; method: string }) => Request;
+        export const contextual: Handler = ({ body, method }) => new Request("/", { body, method });"#,
+        r#"function request({ body, method }) { return fetch("/", { body, method }); }"#,
+        r#"function request({ body, method }) { return new Request("/", { body, method }); }"#,
+        r#"function request(method) { return fetch("/", { method, body: "foo=bar" }); }"#,
+        r#"function request(method) { return new Request("/", { method, body: "foo=bar" }); }"#,
     ];
 
     let fail = vec![