Make RpcResourceState internal in Aspire.Cli and Aspire.Hosting packages

[mitchdenny]

Currently, the class RpcResourceState is public in both Aspire.Cli (src/Aspire.Cli/Backchannel/RpcResourceState.cs) and Aspire.Hosting (src/Aspire.Hosting/Backchannel/RpcResourceState.cs) packages. This issue tracks the work to update the visibility of this class to internal in both locations.

Tasks:

• Update RpcResourceState in src/Aspire.Cli/Backchannel/RpcResourceState.cs to be internal.
• Update RpcResourceState in src/Aspire.Hosting/Backchannel/RpcResourceState.cs to be internal.
• Ensure consumers are updated as appropriate and code compiles successfully.
• Add/change/update any relevant tests if required.

Links:

• Aspire.Cli RpcResourceState
• Aspire.Hosting RpcResourceState