Fix strict null check

src/tsconfig.strictNullChecks.json

@@ -261,7 +261,6 @@
 		"./vs/platform/extensionManagement/node/extensionManagementService.ts",
 		"./vs/platform/extensionManagement/node/extensionManagementUtil.ts",
 		"./vs/platform/extensionManagement/node/extensionsManifestCache.ts",
-		"./vs/platform/extensionManagement/node/multiExtensionManagement.ts",
 		"./vs/platform/extensionManagement/test/electron-browser/extensionManagement.test.ts",
 		"./vs/platform/extensions/common/extensionHost.ts",
 		"./vs/platform/extensions/common/extensions.ts",
@@ -681,6 +680,7 @@
 		"./vs/workbench/services/editor/browser/codeEditorService.ts",
 		"./vs/workbench/services/editor/common/editorGroupsService.ts",
 		"./vs/workbench/services/editor/common/editorService.ts",
+		"./vs/workbench/services/extensionManagement/node/multiExtensionManagement.ts",
 		"./vs/workbench/services/extensions/common/extensionHostProtocol.ts",
 		"./vs/workbench/services/extensions/common/extensions.ts",
 		"./vs/workbench/services/extensions/common/extensionsRegistry.ts",

src/vs/workbench/services/extensionManagement/node/multiExtensionManagement.ts

@@ -209,6 +209,10 @@ export class MultiExtensionManagementService extends Disposable implements IExte
 		}
 
 		const remoteEnv = await connection.getEnvironment();
+		if (!remoteEnv) {
+			return false;
+		}
+
 		return remoteEnv.syncExtensions;
 	}
 }
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