Repro #20551: Filter dropdown only allows filtering on "starts with" (#20581)

frontend/test/metabase/scenarios/question/reproductions/20551-filter-starts-with.cy.spec.js

+import { restore, openProductsTable, filter } from "__support__/e2e/cypress";
+
+describe("issue 20551", () => {
+  beforeEach(() => {
+    restore();
+    cy.signInAsAdmin();
+  });
+
+  it("should allow filtering with includes, rather than starts with (metabase#20551)", () => {
+    openProductsTable({ mode: "notebook" });
+    filter({ mode: "notebook" });
+    cy.findByText("Category").click();
+
+    // Make sure input field is auto-focused
+    cy.focused()
+      .should("have.attr", "placeholder", "Search the list")
+      .type("i");
+
+    // All categories that contain `i`
+    cy.findByText("Doohickey");
+    cy.findByText("Gizmo");
+    cy.findByText("Widget");
+
+    cy.findByText("Gadget").should("not.exist");
+  });
+});