✨(react) add the possibility to hide select label

Based on recent feedbacks this feature was needed. It is important for
the label to still be accessible to screen readers, that's why we
introduced the offscreen class.

Resolve #60

packages/react/src/components/Forms/Select/index.spec.tsx

@@ -1133,5 +1133,37 @@ describe("<Select/>", () => {
       expectMenuToBeClosed(menu);
       expect(valueRendered).toHaveTextContent("Tokyo");
     });
+
+    it("is accessible if the the label is not shown", async () => {
+      render(
+        <CunninghamProvider>
+          <Select
+            label="City"
+            options={[
+              {
+                label: "Paris",
+              },
+              {
+                label: "London",
+              },
+              {
+                label: "New York",
+                disabled: true,
+              },
+              {
+                label: "Tokyo",
+              },
+            ]}
+            hideLabel={true}
+          />
+        </CunninghamProvider>
+      );
+      // Make sure the input is accessible.
+      screen.getByRole("combobox", {
+        name: "City",
+      });
+      const label = screen.getByText("City");
+      expect(Array.from(label.classList)).toContain("offscreen");
+    });
   });
 });