Iterate design of right panel empty state (#12796)

* Add reusable empty state for the right panel

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Update tests

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

* Improve coverage

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

---------

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/components/views/right_panel/EmptyState.tsx

@@ -0,0 +1,42 @@
+/*
+Copyright 2024 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 React, { ComponentType } from "react";
+import { Text } from "@vector-im/compound-web";
+
+import { Flex } from "../../utils/Flex";
+
+interface Props {
+    Icon: ComponentType<React.SVGAttributes<SVGElement>>;
+    title: string;
+    description: string;
+}
+
+const EmptyState: React.FC<Props> = ({ Icon, title, description }) => {
+    return (
+        <Flex className="mx_EmptyState" direction="column" gap="var(--cpd-space-4x)" align="center" justify="center">
+            <Icon width="32px" height="32px" />
+            <Text size="lg" weight="semibold">
+                {title}
+            </Text>
+            <Text size="md" weight="regular">
+                {description}
+            </Text>
+        </Flex>
+    );
+};
+
+export default EmptyState;