Fix Build: Use default() to init custom hash based datastructures

[Shubham8287]

Description of Changes

hashbrown updated their default hasher - https://github.com/rust-lang/hashbrown/blob/master/CHANGELOG.md#v0150---2024-10-01. Which is conflicting with DefaultHashBuilder in our custom types.

start initialising using ::default() to fix this.

API and ABI breaking changes

N/A

Expected complexity level and risk

1

Testing

Successful compiling should be enough.

• [x] Write a test you've completed here.
• [ ] Write a test you want a reviewer to do here, so they can check it off when they're satisfied.

[Centril]

I'm a bit confused here as to what is broken about the current build, as master seems to pass when doing cargo clippy --tests --benches --all.