feat: allow tenant admin to remount secret engines on tenant prefix

policies/tenant-admins.policy.hcl

@@ -5,3 +5,11 @@ path "${tenant_prefix}/*" {
 path "sys/mounts/${tenant_prefix}/*" {
   capabilities = ["create", "update", "read", "delete", "list"]
 }
+
+path "sys/remount" {
+  capabilities = ["update"]
+  allowed_parameters = {
+    from = "${tenant_prefix}/*"
+    to = "${tenant_prefix}/*"
+  }
+}