Bug: [PERF] Remove redundant heap allocation present in the logging framework



Use here, below, and in similar places, the`format_args!()` macro instead, to omit redundant allocations produced by the `format!()` macro (as it returns a new `String`).

## Code Snippets

- https://github.com/juspay/hyperswitch/blob/597ec16907a83ce228228b8c00e329495ade117b/crates/router_env/src/logger/formatter.rs#L208
- https://github.com/juspay/hyperswitch/blob/597ec16907a83ce228228b8c00e329495ade117b/crates/router_env/src/logger/formatter.rs#L214


### Steps for Resolution

While taking up this issue, please document the solution you are going forward with, also include benchmarks or evidence as to how extra heap allocations are avoided. (please use this issue itself for discussion and the approach documentation). 
(Optional) in-code documentation is always encouraged.
diff --git a/crates/router_env/src/logger/formatter.rs b/crates/router_env/src/logger/formatter.rs
index a015f0e48ef..ce2fd74e0e8 100644
--- a/crates/router_env/src/logger/formatter.rs
+++ b/crates/router_env/src/logger/formatter.rs
@@ -205,13 +205,14 @@ where
         map_serializer.serialize_entry(VERSION, &self.version)?;
         #[cfg(feature = "vergen")]
         map_serializer.serialize_entry(BUILD, &self.build)?;
-        map_serializer.serialize_entry(LEVEL, &format!("{}", metadata.level()))?;
+        map_serializer.serialize_entry(LEVEL, &format_args!("{}", metadata.level()))?;
         map_serializer.serialize_entry(TARGET, metadata.target())?;
         map_serializer.serialize_entry(SERVICE, &self.service)?;
         map_serializer.serialize_entry(LINE, &metadata.line())?;
         map_serializer.serialize_entry(FILE, &metadata.file())?;
         map_serializer.serialize_entry(FN, name)?;
-        map_serializer.serialize_entry(FULL_NAME, &format!("{}::{}", metadata.target(), name))?;
+        map_serializer
+            .serialize_entry(FULL_NAME, &format_args!("{}::{}", metadata.target(), name))?;
         if let Ok(time) = &time::OffsetDateTime::now_utc().format(&Iso8601::DEFAULT) {
             map_serializer.serialize_entry(TIME, time)?;
         }

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

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

## Description
Updated macro invocation from the format! to format_args! 


### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

<!--
Provide links to the files with corresponding changes.

Following are the paths where you can find config files:
1. `config`
2. `crates/router/src/configs`
3. `loadtest/config`
-->


## Motivation and Context
[1293](https://github.com/juspay/hyperswitch/issues/1293)


## How did you test it?

## Checklist
<!-- Put an `x` in the boxes that apply -->

- [X] I formatted the code `cargo +nightly fmt --all`
- [X] I addressed lints thrown by `cargo clippy`
- [ ] I reviewed submitted code
- [ ] I added unit tests for my changes where possible
- [ ] I added a [CHANGELOG](/CHANGELOG.md) entry if applicable
