[Identity] No more inMemoryPersistence! (Azure#14530)

Now that we've released 2.0.0-beta.1 and the Identity hotfix that I
wanted to release, I was able to sit down and start writing a sample
showcasing some of the "bugs" I found. This helped me bounce against
the code and eventually figure out that it was in fact _me_ who had
written a bug!

This if:

```ts
if (this.publicApp && this.confidentialApp) {
  return;
}
```

in the code that defines the configuration for Node.js was causing the
MSAL client to be defined multiple times, rendering the in-memory cache
as useless.

The solution? To switch `&&` to `||`.

It seems obvious in retrospective!

This means that there's no need neither for the `inMemoryCache`, nor for
the line that I used to "read" from the cache. Therefore:

Fixes Azure#14372
Fixes Azure#14373

Author: sadasant

sdk/identity/identity/src/msal/nodeFlows/nodeCommon.ts

@@ -9,7 +9,6 @@ import { DeveloperSignOnClientId } from "../../constants";
 import { IdentityClient, TokenCredentialOptions } from "../../client/identityClient";
 import { TokenCachePersistenceOptions } from "../../tokenCache/persistencePlatforms";
 import { TokenCachePersistence } from "../../tokenCache/TokenCachePersistence";
-import { inMemoryPersistence } from "../../tokenCache/InMemoryPersistence";
 import { resolveTenantId } from "../../util/resolveTenantId";
 import { TokenCache } from "../../tokenCache/types";
 import { CredentialFlowGetTokenOptions } from "../credentials";
@@ -56,10 +55,6 @@ export abstract class MsalNode extends MsalBaseUtilities implements MsalFlow {
 
     if (options.tokenCachePersistenceOptions) {
       this.tokenCache = new TokenCachePersistence(options.tokenCachePersistenceOptions);
-    } else {
-      // To allow silent authentications on the same credential, we provide a very simple in memory token cache.
-      // It can't be used to re-use the account information returned from the authenticate() method.
-      this.tokenCache = inMemoryPersistence();
     }
   }
 
@@ -102,7 +97,7 @@ export abstract class MsalNode extends MsalBaseUtilities implements MsalFlow {
       });
     }
 
-    if (this.publicApp && this.confidentialApp) {
+    if (this.publicApp || this.confidentialApp) {
       return;
     }
 
@@ -210,11 +205,6 @@ To work with multiple accounts for the same Client ID and Tenant ID, please prov
       scopes
     };
 
-    // Currently we need to call getAllAccounts before the silent request is attempted.
-    // The MSAL team is actively investigating why this is necessary.
-    // TODO: Remove this once this is no longer necessary.
-    await this.publicApp?.getTokenCache().getAllAccounts();
-
     try {
       this.logger.info("Attempting to acquire token silently");
       const response = await this.publicApp!.acquireTokenSilent(silentRequest);