Kill off references to deprecated getStoredDevice and getStoredDevicesForUser (#11152)

* Use new `CryptoEvent.VerificationRequestReceived` event

https://github.com/matrix-org/matrix-js-sdk/pull/3514 deprecates
`CryptoEvent.VerificationRequest` in favour of
`CryptoEvent.VerificationRequestReceived`. Use the new event.

* Factor out `getDeviceCryptoInfo` function

I seem to be writing this logic several times, so let's factor it out.

* Factor out `getUserDeviceIds` function

Another utility function

* VerificationRequestToast: `getStoredDevice` -> `getDeviceCryptoInfo`

* SlashCommands: `getStoredDevice` -> `getDeviceCryptoInfo`

* MemberTile: `getStoredDevicesForUser` -> `getUserDeviceIds`

* Remove redundant mock of `getStoredDevicesForUser`

src/utils/crypto/deviceInfo.ts

@@ -0,0 +1,67 @@
+/*
+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 { Device, MatrixClient } from "matrix-js-sdk/src/matrix";
+
+/**
+ * Get crypto information on a specific device.
+ *
+ * Only devices with Crypto support are returned. If the MatrixClient doesn't support cryptography, `undefined` is
+ * returned.
+ *
+ * @param client  - Matrix Client.
+ * @param userId  - ID of the user owning the device.
+ * @param deviceId - ID of the device.
+ * @param downloadUncached - If true, download the device list for users whose device list we are not
+ *    currently tracking. Defaults to false.
+ *
+ * @returns Information on the device if it is known.
+ */
+export async function getDeviceCryptoInfo(
+    client: MatrixClient,
+    userId: string,
+    deviceId: string,
+    downloadUncached?: boolean,
+): Promise<Device | undefined> {
+    const crypto = client.getCrypto();
+    if (!crypto) {
+        // no crypto support, no device.
+        return undefined;
+    }
+
+    const deviceMap = await crypto.getUserDeviceInfo([userId], downloadUncached);
+    return deviceMap.get(userId)?.get(deviceId);
+}
+
+/**
+ * Get the IDs of the given user's devices.
+ *
+ * Only devices with Crypto support are returned. If the MatrixClient doesn't support cryptography, an empty Set is
+ * returned.
+ *
+ * @param client  - Matrix Client.
+ * @param userId  - ID of the user to query.
+ */
+
+export async function getUserDeviceIds(client: MatrixClient, userId: string): Promise<Set<string>> {
+    const crypto = client.getCrypto();
+    if (!crypto) {
+        return new Set();
+    }
+
+    const deviceMap = await crypto.getUserDeviceInfo([userId]);
+    return new Set(deviceMap.get(userId)?.keys() ?? []);
+}