Set grey collection status in Qdrant 1.10

[timvisee]

Implements #3962.

In #3962 we've added the grey collection status. We now start actually reporting it.

It replaces the optimizer status message we had before, because using the grey collection status is more elegant.

We couldn't use it right away, but needed to delay it by one version to allow us making all clients compatible.

Tasks

• Add 'trigger optimizers' button in web UI? (Feature request: add 'trigger optimizers' button to collection info qdrant-web-ui#179)

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