switch to switchboard-on-demand crate

[mgild]

This pull request updates the Switchboard dependency and refactors related imports to use the new package structure. The changes ensure compatibility with the latest Switchboard API and improve code organization.

Dependency update:

• Updated the Switchboard dependency in cli/Cargo.toml from switchboard-on-demand-client version 0.2.12 to switchboard-on-demand version 0.9.5, with specific features enabled (solana-v2, client).

Code import refactoring:

• Changed imports in cli/src/handler.rs to use SbContext from switchboard_on_demand::client::pull_feed instead of the old client package.
• Updated imports in cli/src/instructions.rs to use CrossbarClient, FetchUpdateParams, and PullFeed from the new switchboard_on_demand package structure, and moved QueueAccountData to the top-level package.