Issue:
[BUG]: 2-Letter State abbreviation is not accepted

### Bug Description

Currently 2-Letter State abbreviation is not accepted, in `billing.state` if you pass 2 letter valid state it should not throw an error

### Expected Behavior

Both 2 letter and full state name shall be accepted in `billing.state` and should be manipulated according to the requirements before sending it to the connector.

### Actual Behavior

Currently 2-Letter State abbreviation is not accepted, in `billing.state` if you pass 2 letter valid state it should not throw an error

### Steps To Reproduce

Provide an unambiguous set of steps to reproduce this bug. Include code or configuration to reproduce, if relevant.
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2. Click on '....'
3. Scroll down to '....'


### Context For The Bug

_No response_

### Environment

Are you using hyperswitch hosted version? Yes/No
If yes, please provide the value of the `x-request-id` response header to help us debug your issue.

If not (or if building/running locally), please provide the following details:
1. Operating System or Linux distribution:
2. Rust version (output of `rustc --version`): ``
3. App version (output of `cargo r --features vergen -- --version`): ``


### Have you spent some time checking if this bug has been raised before?

- [X] I checked and didn't find a similar issue

### Have you read the Contributing Guidelines?

- [X] I have read the [Contributing Guidelines](https://github.com/juspay/hyperswitch/blob/main/docs/CONTRIBUTING.md)

### Are you willing to submit a PR?

Yes, I am willing to submit a PR!

Resolution:
<think>
PR Context:
- Title: fix(connector): accept state abbreviation in 2 letter
- Merged: 2024-05-15T11:24:00Z
- Files changed: 2 files
- Commits: 5 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [X] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
Accept `billing.state` with 2-letter abbreviation for US and CA

### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment vari
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** fix(connector): accept state abbreviation in 2 letter (#4646)
Co-authored-by: hyperswitch-bot[bot] <
Files to modify:


**crates/common_enums/src/enums.rs**
  Modify existing code

**crates/router/src/connector/utils.rs**
  Modify existing code