Speed up failed event retrying

### Your use case

#### What would you like to do?
Reduce the time taken to resend failed events

#### Why would you like to do it?
To improve timeline responsiveness on flaky connections/home servers

#### How would you like to achieve it?
By exponentially backing off the retry mechanism from 500ms, 1 second, 5 seconds, 10 seconds instead of always using a 10 second polling mechanism.

### Have you considered any alternatives?

_No response_

### Additional context

https://github.com/vector-im/element-android/pull/2902