fix: added back disconnectRequired flag assignment

[Davide-Gheri]

Adds back Redis connection close logic added in #644 but removed in #1038

Closes #1192

[alko89]

Is the disconnectRequired flag even necessary? Should work fine with simply calling disconnect?

onModuleDestroy() {
      this.redis?.disconnect(false);
}

[Davide-Gheri]

The idea behind the flag was that if you provide a Redis instance yourself, this library should not be responsible of closing its connection.

[kkoomen]

Release in v0.3.3 on NPM.