Chunk utilization is incorrect for transferred chunks

[rfratto]

We first noticed that loki_ingester_chunk_utilization_sum was being reported as NaN. After some investigation, it seems clear that the only cause would be transferred chunks: they don't have an uncompressed size, block size, target size, or cut block size set. This will always result in a division by zero when calculating utilization.

To Reproduce
Steps to reproduce the behavior:

1. Started Loki (v1.2.0). Make sure to launch in microservices mode.
2. Restart the ingesters.
3. Force a flush across the new ingesters.
4. Observe the value for loki_ingester_chunk_utilization_sum.

Expected behavior
The value should not be NaN.

[rfratto]

This should probably wait for #1411 to get merged first.

[rfratto]

Another effect of this is that the first chunk per stream after a transfer be very underutilized and only be able to store up to 10 log lines before running out of space.

[stale]

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