build: bump required language level to 1.24, compiler to 1.25 (#10248)

(After 2.0.1)

lib/api/api_test.go

@@ -888,7 +888,7 @@ func TestHtmlFormLogin(t *testing.T) {
 				t.Errorf("Unexpected non-200 return code %d at %s", resp.StatusCode, noAuthPath)
 			}
 			if hasSessionCookie(resp.Cookies()) {
-				t.Errorf("Unexpected session cookie at " + noAuthPath)
+				t.Errorf("Unexpected session cookie at %s", noAuthPath)
 			}
 		})
 	}