Let MCP connect to multiple spaces

The mcp connector requires selecting a single space that the agent has access to. However, for many agents, only one connector for a given service can be activated at a time, so we are limited to the agent (Claude, ChatGPT, etc.) only being able to interact with one of our spaces.

Ideally, we would be able to select multiple spaces for the agents to have access to, while still being allowed to exclude access to certain spaces.