Better lifecycle handling (#242758)

I moved to a factory model because there was just so much that needed to be async.

I think the amount of async code will be reduced in the future as we remove some migration logic, but this makes sure we don't accidentally create instances without awaiting their initialization.

extensions/microsoft-authentication/src/common/cachePlugin.ts

@@ -6,7 +6,7 @@
 import { ICachePlugin, TokenCacheContext } from '@azure/msal-node';
 import { Disposable, EventEmitter, SecretStorage } from 'vscode';
 
-export class SecretStorageCachePlugin implements ICachePlugin {
+export class SecretStorageCachePlugin implements ICachePlugin, Disposable {
 	private readonly _onDidChange: EventEmitter<void> = new EventEmitter<void>();
 	readonly onDidChange = this._onDidChange.event;