[ML] min_version for anomaly detector model state is wrong

[droberts195]

The min_version field for anomaly detector model state that stops model snapshots being loaded on nodes that are too old to understand then is currently incorrect. It is set to version 6.4.0, when we have updated the model state format more recently than that.

It's too late to correct released versions, but we can make some improvements:

1. For 7.10.0 we can update the constant to the version where the previous breaking change to model state was made
2. For 7.11.0 we can update the constant to version 7.11.0 to reflect the changes being made for time series decomposition and change point detection

[droberts195]

1. For 7.10.0 we can update the constant to the version where the previous breaking change to model state was made

I believe this was the change made in 7.9.0 in #1340