Addresses a beginning component of #6255
## Description - Add `context.Context` to Privval interface This pr does not introduce context into our custom privval connection protocol because this will be removed in the next release. When this pr is released.
## Description - Query validator key when a remote signer is used. This is supported gRPC remote signing and filePV only. Closes: #3009
Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>