refactor(routers,connectors) : Remove unused functions in `crates/router/src/connector/utils.rs`

 ## Analyze and Remove Unused Functions from `crates/router/src/connector/utils.rs`

### Description:

There are functions in the crates/router/src/connector/utils.rs file that appear to be unused across the router crate. For 

example:
•	validate_currency is defined in utils.rs but is not used anywhere in the codebase. This function can be safely removed.

###  Task:
•	Perform a comprehensive analysis of all the functions present in crates/router/src/connector/utils.rs.
•	Identify any functions that are not referenced anywhere in the router crate which are in utils.
•	Remove such unused functions to reduce dead code and improve maintainability.
<think>
PR Context:
- Title: refactor: remove unused functions
- Merged: 2025-05-14T10:29:02Z
- Files changed: 1 files
- Commits: 2 commits

Implementation approach:
crates/router/src/connector/utils.rs

## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
Removed functions that are not used in other files and removed imports that are only referenced by the unused functions.
[crates/router/src/connector/utils.rs](https://github.com/juspay/hyperswitch/blob
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** refactor: remove unused functions (#7994)
Files to modify:


**crates/router/src/connector/utils.rs**
  Remove:
    - function: pub::get_http_header
    - function: pub::to_boolean
    - function: pub::get_connector_meta
    - function: pub::base64_decode
    - function: pub::to_currency_base_unit_from_optional_amount
    - function: pub::get_amount_as_string
    - function: pub::get_amount_as_f64
    - function: pub::to_currency_base_unit
    - function: pub::to_currency_lower_unit
    - function: pub::construct_not_implemented_error_report
    - function: pub::to_currency_base_unit_with_zero_decimal_check
    - function: pub::to_currency_base_unit_asf64
    - function: pub::str_to_f32
    - function: pub::collect_values_by_removing_signature
    - function: pub::collect_and_sort_values_by_removing_signature
    - function: pub::get_webhook_merchant_secret_key
    - function: pub::construct_captures_response_hashmap
    - function: pub::is_manual_capture
    - function: pub::generate_random_bytes
    - function: pub::validate_currency
    - function: pub::get_timestamp_in_milliseconds
    - function: pub::get_mandate_details

**Commit 2:** refactor: remove unused functions (#7994)
Files to modify:


**crates/router/src/connector/utils.rs**
  Remove:
    - function: pub::get_http_header
    - function: pub::to_boolean
    - function: pub::get_connector_meta
    - function: pub::base64_decode
    - function: pub::to_currency_base_unit_from_optional_amount
    - function: pub::get_amount_as_string
    - function: pub::get_amount_as_f64
    - function: pub::to_currency_base_unit
    - function: pub::to_currency_lower_unit
    - function: pub::construct_not_implemented_error_report
    - function: pub::to_currency_base_unit_with_zero_decimal_check
    - function: pub::to_currency_base_unit_asf64
    - function: pub::str_to_f32
    - function: pub::collect_values_by_removing_signature
    - function: pub::collect_and_sort_values_by_removing_signature
    - function: pub::get_webhook_merchant_secret_key
    - function: pub::construct_captures_response_hashmap
    - function: pub::is_manual_capture
    - function: pub::generate_random_bytes
    - function: pub::validate_currency
    - function: pub::get_timestamp_in_milliseconds
    - function: pub::get_mandate_details
{"issue_number": 7928, "pr_number": 7994, "commits_count": 2, "files_changed": 1, "response_length": 3068, "file_count": 5, "needs_breakdown": false}