[FEATURE] Hot change kyuubi sql engine

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

### Search before asking

- [X] I have searched in the [issues](https://github.com/apache/kyuubi/issues?q=is%3Aissue) and found no similar issues.

### Describe the feature

For the kyuubi session that has been created, the sql engine of kyuubi can be hot-switched in some way

### Motivation

Kyuubi serves as a unified sql entry, and one kyuubi service acts as a proxy for multiple sql engines, but switching engines requires creating a new kyuubi session, which is cumbersome to use and increases the difficulty of task management.

### Describe the solution

set kyuubi.engine.type=****;(trino,flink,spark)

### Additional context

_No response_

### Are you willing to submit PR?

- [ ] Yes. I would be willing to submit a PR with guidance from the Kyuubi community to improve.
- [X] No. I cannot submit a PR at this time.

Start by tracing how an existing Kyuubi session selects and owns its SQL engine, including the paths for Spark, Flink, and Trino. Define how a live session would accept and apply kyuubi.engine.type changes, then verify that switching preserves session behavior without requiring a new session.

Written by the indexing model from the issue text.