Add .well-known config option to force disable encryption on room creation (#11120)

* force disable encryption on room creation

* test allowChangingEncryption

* move into utils/room directory

* tests

* unit test CreateRoomDialog

* remove debug

* wait for constructor promises to settle

* test case for force_disable

* comment

* set forced value after resolving checkUserIsAllowedToChangeEncryption

* tidy and comments

* use label text in test

src/utils/room/shouldForceDisableEncryption.ts

@@ -0,0 +1,39 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { MatrixClient } from "matrix-js-sdk/src/matrix";
+
+import { getE2EEWellKnown } from "../WellKnownUtils";
+
+/**
+ * Check e2ee io.element.e2ee setting
+ * Returns true when .well-known e2ee config force_disable is TRUE
+ * When true all new rooms should be created with encryption disabled
+ * Can be overriden by synapse option encryption_enabled_by_default_for_room_type ( :/ )
+ * https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#encryption_enabled_by_default_for_room_type
+ *
+ * @param client
+ * @returns whether well-known config forces encryption to DISABLED
+ */
+export function shouldForceDisableEncryption(client: MatrixClient): boolean {
+    const e2eeWellKnown = getE2EEWellKnown(client);
+
+    if (e2eeWellKnown) {
+        const shouldForceDisable = e2eeWellKnown["force_disable"] === true;
+        return shouldForceDisable;
+    }
+    return false;
+}