Don't render redacted edits in timeline

[turt2live]

I see two redaction bars for a message edited once, when I would have expected a single bar with 'edited' next to it

[turt2live]

ftr this is completely the fault of the redaction algorithm: relationships between events are not spared the pruning, therefore the client loses context on the events. Riot/Synapse should probably track the relationship external to the event, or we bump the room version to fix the redaction algorithm.

[bwindels]

This requires a change to the MSC and backend support to fix properly, so marking as blocked.