Enable spatial types support in Search

[AlexGhiondea]

Once the Azure Core change (#10592) is merged, we need to re-enabled the APIs in Search to support it.

[heaths]

When we do this, we could remove the proxy classes for Microsoft.Spatial and instead use adapters to create GeoJson types. This would not only reduce the amount of code to maintain, but also remove the intentional duplication in SpatialFormatter to improve perf (no reason to allocate extra).

[AlexGhiondea]

This is done now.

[heaths]

The proxies for Microsoft.Spatial still exist but the comment implies the intention was to remove them. That's not what we actually want to do, though, right? So we can still support Microsoft.Spatial types? Maybe the comment is just misleading.

/cc @tg-msft @Mohit-Chakraborty @brjohnstmsft