Coverage update

[leodziki]

Description

In this pull request, I have taken the initiative to streamline code generation and message parsing by removing superfluous elements such as the prost and codegen functions, which were deemed unnecessary in the current context.

Moreover, I have placed a strong emphasis on eliminating hardcoding within the codebase, a crucial step towards enhancing maintainability and flexibility in the system.

Ensuring consistency in string formats from raw strings (r#"") to regular strings ("") remains a key aspect of this update. While raw strings are typically utilized for intricate JSON data with special escape sequences like \n or ", the transition to regular strings can offer a more streamlined representation when these complex escape sequences are not present.

Fixes #1445

Type of change

• [ x ] New feature (non-breaking change which adds functionality)
• [ x ] Breaking change (fix or feature that would cause existing functionality to
  not work as expected)

How Has This Been Tested?

Both bazel test and cargo test passed. Check coverage status using "cargo +nightly llvm-cov test --all --tests --branch --html"

Checklist

• [ x ] Tests added/amended
• [ x ] bazel test //... passes locally

---

This change is