[TypeSpec Authoring] Agent should not ask whether to remove latest preview during version evolution

## Description

When adding a new preview or stable API version in a version evolution scenario, the agent currently asks the user whether to remove the latest preview version. Per Mark's guidelines, the latest preview should always be removed — the agent should not prompt the user for this decision.

## Current Behavior

During version evolution (e.g., adding a new preview or stable version), the agent asks the user:
> "Should the latest preview version be removed?"

This adds unnecessary friction and contradicts the established guidelines.

## Expected Behavior

The agent should automatically remove the latest preview version without asking the user, following Mark's guidelines. The removal should be handled as part of the standard version evolution workflow.

## Parent Issue

Part of #14739

No file, test, or entry point is named. Start by searching for the prompt text "Should the latest preview version be removed?" and trace the version-evolution workflow. Done means adding a preview or stable version removes the latest preview automatically without prompting, following the stated guidelines.

Written by the indexing model from the issue text.