Stop reading URL parameters from inside the call path

The view models reached for getUrlParams() — and so window.location —
from deep inside the call path: CallViewModel, MediaDevices, Publisher,
LocalMember and the footer view model. An embedded Element Call has no URL
of its own, so these values have to arrive as arguments instead.

Add the relevant options to CallViewModelOptions, to the MediaDevices and
Publisher constructors, to createLocalMembership$ and enterRTCSession, and
to createCallFooterViewModel. The remaining React consumers read the
context added in the previous commit. AppViewModel now takes its audio
output options too, moving that URL read out to main.tsx, where the app
shell can act as the adapter.

The new CallViewModelOptions fields are optional, defaulting to what the
URL parameters resolve to outside widget mode; the MediaDevices and
Publisher arguments are required, so that every construction site has to
be explicit.

useTheme.test.ts mocked the UrlParams module with a factory, so it needed
updating to mock the hook rather than getUrlParams.

No functional change.

src/App.tsx

@@ -5,14 +5,7 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-import {
-  type FC,
-  type JSX,
-  Suspense,
-  useEffect,
-  useMemo,
-  useState,
-} from "react";
+import { type FC, type JSX, Suspense, useEffect, useState } from "react";
 import { BrowserRouter, Route, useLocation, Routes } from "react-router-dom";
 import * as Sentry from "@sentry/react";
 import { TooltipProvider } from "@vector-im/compound-web";
@@ -32,7 +25,6 @@ import { ProcessorProvider } from "./livekit/TrackProcessorContext";
 import { type AppViewModel } from "./state/AppViewModel";
 import { MediaDevicesContext } from "./MediaDevicesContext";
 import {
-  getUrlParams,
   HeaderStyle,
   UrlParamsProvider,
   useUrlParams,
@@ -75,6 +67,12 @@ const ThemeProvider: FC<SimpleProviderProps> = ({ children }) => {
   return children;
 };
 
+/** Wraps the app in an {@link AppBar}, if the params ask for one. */
+const MaybeAppBar: FC<SimpleProviderProps> = ({ children }) => {
+  const { header } = useUrlParams();
+  return header === HeaderStyle.AppBar ? <AppBar>{children}</AppBar> : children;
+};
+
 interface Props {
   vm: AppViewModel;
 }
@@ -91,9 +89,6 @@ export const App: FC<Props> = ({ vm }) => {
       .catch(logger.error);
   });
 
-  // Since we are outside the router component, we cannot use useUrlParams here
-  const { header } = useMemo(getUrlParams, []);
-
   const content = loaded ? (
     <ClientProvider>
       <MediaDevicesContext value={vm.mediaDevices}>
@@ -123,11 +118,7 @@ export const App: FC<Props> = ({ vm }) => {
             <ThemeProvider>
               <TooltipProvider>
                 <Suspense fallback={null}>
-                  {header === HeaderStyle.AppBar ? (
-                    <AppBar>{content}</AppBar>
-                  ) : (
-                    content
-                  )}
+                  <MaybeAppBar>{content}</MaybeAppBar>
                 </Suspense>
               </TooltipProvider>
             </ThemeProvider>