Client class should throw a custom exception if the capability is unsupported #430

Is your feature request related to a problem? Please describe.
Currently, MCP Client class in https://github.com/modelcontextprotocol/typescript-sdk/blob/main/src/client/index.ts throws Error when a capability isn't supported by a server. While building any MCP client applications, this makes it hard to know, when i call client.listPrompts and get back an exception - if the exception was because of an actual failure or because the capability isn't supported

Describe the solution you'd like
Client class should throw a custom exception like UnsupportedCapabilityException when the capability itself isn't supported - this makes it easy to write clients around this logic

Describe alternatives you've considered
Currently i am working around this by grepping the returned exception message to see if it contains the string does not support. This is very brittle and can break easily if the exception message changes