statestore query API: remove 'value' prefix from key names in query JSON

[dmitsh]

What content needs to be created or modified?

There is a minor change in statestore query API syntax.
The details are here: dapr/components-contrib#1490

Describe the solution you'd like

Where should the new material be placed?

The associated pull request from dapr/dapr, dapr/components-contrib, or other Dapr code repos

dapr/components-contrib#1491

Additional context

[dmitsh]

/assign

[msfussell]

Merged