.github/workflows/ci-conda-known-test-failures.json: Add failure seen in https://github.com/sagemath/sage/actions/runs/6827937663/job/18571052628\#step:11:12362

Author: Matthias Koeppe

.github/workflows/ci-conda-known-test-failures.json

@@ -5,6 +5,9 @@
     "sage.combinat.cluster_algebra_quiver.quiver": {
         "failed": true
     },
+    "sage.geometry.cone": {
+        "failed": true
+    },
     "sage.groups.matrix_gps.finitely_generated_gap": {
         "failed": true
     },
@@ -17,6 +20,9 @@
     "sage.matrix.matrix2": {
         "failed": true
     },
+    "sage.matrix.matrix_integer_sparse": {
+        "failed": true
+    },
     "sage.misc.lazy_import": {
         "failed": true
     },