bmp rust toolchain to 1.97.1 (#19160)

## Description
This PR bumps the rust toolchain to 1.97.1 since 1.99 was recently
released and we try to stay 2 versions behind it.
<!--
Explain what this PR does and why.

This section is intentionally flexible:
- Describe the problem
- Explain your approach
- Include technical details if relevant

Good examples:
- "In this PR, I fixed..."
- "In this PR, I added support for..."
- "This change improves X by..."

Write as much or as little as needed for reviewers to understand your
changes.
-->

## User-facing changes (Release notes)
<!--
This section is used (mostly as-is) for https://www.nushell.sh/blog/

Describe how Nushell behavior changes from a user's perspective.
Do NOT describe internal Rust changes here.

Write in a release note style, for example:
- "Added support for..."
- "Fixed an issue where..."
- "Nushell now supports..."
- "Improved performance of..."

If your changes do NOT affect users (internal refactors, cleanup, etc.),
just write:
- "n/a"
- "nan"
- or similar

This tells us the change should not appear in the changelog.

Tips:
- Focus on observable behavior
- Include examples if helpful
- Keep it concise

You can:
- Write a short paragraph (will appear as a bullet point), OR
- Use headings (###) if your change needs more structure

Avoid writing things like:
- "In this PR, I refactored..."
- "This updates internal code..."

You may leave this blank until the PR is ready.
-->

## Additional notes
<!--
Optional.

Examples:
- fixes #123
- closes #456
- related #789

Anything else reviewers should know.
Remove this section if not needed.
-->

Cargo.toml

@@ -1,7 +1,7 @@
 [workspace.package]
 authors = ["The Nushell Project Developers"]
 edition = "2024"
-rust-version = "1.96.1"
+rust-version = "1.97.1"
 license = "MIT"
 version = "0.116.2"
 

rust-toolchain.toml

@@ -14,4 +14,4 @@ profile = "default"
 # so that we give repo maintainers and package managers a chance to update to a more
 # recent version of rust. However, if there is a "cool new feature" that we want to
 # use in nushell, we may opt to use the bleeding edge stable version of rust.
-channel = "1.96.1"
+channel = "1.97.1"