[Bug]: PubSubReadEvalutar for DirectRunner introduces very long timeout

### What happened?

#16126 Made an undocumented change when upgrading the pubsub library by adding a 30 second timeout.

https://github.com/apache/beam/commit/acff5d1f29246c44513dbe2fe3da53567448bc14#diff-01a2c3bce792ce6a31018973e914a42b7150d06dc9c490a4640148e06ffdfa01R690

This timeout makes streaming pipeline windows with many subscriptions to listen to lag 30*(number of subscriptions) seconds when not all topics are generating messages, causing a minute long window in my case to be emitted after 30 minutes if it has a few messages, or an hour depending on the luck of the scheduler.

### Issue Priority

Priority: 2 (default / most bugs should be filed as P2)

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