Enable worldSafeExecuteJavaScript.

This has no effect on our use of executeJavaScript, and will become
the default in Electron 12, but for now it silences a warning in
development mode.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

app/main/index.ts

@@ -90,7 +90,8 @@ function createMainWindow(): Electron.BrowserWindow {
 			enableRemoteModule: true,
 			nodeIntegration: true,
 			partition: 'persist:webviewsession',
-			webviewTag: true
+			webviewTag: true,
+			worldSafeExecuteJavaScript: true
 		},
 		show: false
 	});

app/renderer/js/components/webview.ts

@@ -64,7 +64,8 @@ export default class WebView extends BaseComponent {
 				name="${this.props.name}"
 				webpreferences="
 					contextIsolation=${!this.props.nodeIntegration},
-					spellcheck=${Boolean(ConfigUtil.getConfigItem('enableSpellchecker'))}
+					spellcheck=${Boolean(ConfigUtil.getConfigItem('enableSpellchecker'))},
+					worldSafeExecuteJavaScript=true
 				">
 			</webview>
 		`;