Updating `templateParameter` name to `unsafeParameter`

### Prerequisites

- [x] Search the [current open issues](https://github.com/googleapis/genai-toolbox/issues)

### What are you trying to do that currently feels hard or impossible?

The current `templateParameter` might be less intuitive towards user that the usage of template parameter might have higher risks for sql injection. Because of this, Toolbox recommend users to use regular parameters instead of template parameter whenever possible.

There's another issue that address the possible mitigations to reduce security risks #779 for template parameter.

### Suggested Solution(s)

Consider renaming `templateParameter` to `unsafeParameter` or `dangerousTemplateParameter`.

### Alternatives Considered

_No response_

### Additional Details

_No response_

Start by searching the repository for uses of `templateParameter`, then read issue #779 for the related security context. Determine the affected user-facing references and what consistency is required for a completed rename; the issue does not identify specific files or tests.

Written by the indexing model from the issue text.