Refactor realign_keys method in faststream/response/response.py

[ApusBerliozi]

Description

Refactored realign_keys method, kept it in the response.py, but split it in two and changed an approach for index forming

Fixes #2987

Type of change

Please delete options that are not relevant.

• Documentation (typos, code examples, or any documentation updates)
• Refactoring
• New feature (a non-breaking change that adds functionality)
• Breaking change (a fix or feature that would disrupt existing functionality)
• This change requires a documentation update

Checklist

• My code adheres to the style guidelines of this project (just lint shows no errors)
• I have conducted a self-review of my own code
• I have made the necessary changes to the documentation
• My changes do not generate any new warnings
• I have added tests to validate the effectiveness of my fix or the functionality of my new feature
• Both new and existing unit tests pass successfully on my local environment by running just test-coverage
• I have ensured that static analysis tests are passing by running just static-analysis
• I have included code examples to illustrate the modifications