Fixed compiler warnings and lints added in Rust 1.89

[maciejdudko]

What was changed

Fixed compiler warnings and lints added in Rust 1.89, specifically:

• Hidden lifetimes warning
• Flattening if-let chains
• Using std::slice::from_ref to avoid cloning

Why?

Removes warnings from compiler output, and CI would start failing when we upgrade to Rust 1.89.

Checklist

2. How was this tested:
   Ran cargo lint and cargo test-lint locally using Rust 1.89.