Every single added MCP tries to auth immediately after configuring in bulk

### Describe the bug

My org uses an MCP registry to make an increasing number of MCP servers available for our developers. Via CLI tooling, we pull from a given registry, transform the json spec to match the tooling schema, and then update the config on the developer's machine.

This approach has worked well with VSCode and opencode. MCPs are added to the config, and the tools are aware of the MCPs without immediately triggering auth. Upon the users invoking MCPs, agents recognise that the MCP is missing auth, then triggers an auth flow (normally through opening a browser tab itself).

Copilot CLI does not seem to work in the same way. It does recognise the MCPs, but the next time a user opens the copilot CLI (even without running any prompt) every single MCP server will try to run its auth flow at once. It's also not a suggestion as VSCode does: a new browser tab opens for every MCP, and we're talking about potentially dozens of MCPs being installed in one go.

### Affected version

GitHub Copilot CLI 1.0.3.

### Steps to reproduce the behavior

1. Add a number of MCPs requiring auth to `/home//.copilot/mcp-config.json` directly (editing JSON manually or programmatically)
2. Start copilot CLI via the `copilot ` command.

### Expected behavior

We would appreciate the behavior changing so that one (or all) of these behaviors occur instead:

1. MCP auth can be deferred to the point of usage (i.e. not trigger auth as soon as they're added externally).
2. CLI behavior can be configured to prevent too many tabs opening at the same time.

### Additional context

Confirmed happening in both MacOs and Ubuntu Linux, zsh, multiple terminal emulators.