Issue:
[REFACTOR]: [Klarna] Remove Default Case Handling

### :memo: Feature Description

- We utilize match statements to make pivotal decisions, such as generating requests based on the payment method type and managing responses received from the connector. 
- These conditions generally go hand in hand with enum variants. 
- Default case is used because a match statement needs to be exhaustive i.e. every variant needs to be covered. 
- So, if all the explicit cases are handled then default is used to handle the rest.
- Each connector have these match statements but many of them don’t provide reference to each variant in their default case, rather a `_` is put to handle all the other cases. 
- This approach carries a risk because developers may inadvertently overlook the need for explicit handling of the new cases.

### :hammer: Possible Implementation

- Instead of relying on a default match case `_`, developers should handle each and every variant explicitly. 
- By doing so, if there are any changes in the future, they can readily assess the impact of their modifications simply by compiling the code.
- You can check this PR for further reference https://github.com/juspay/hyperswitch/pull/1955

:bookmark: Note: All the changes needed should be contained within `hyperswitch/crates/router/src/connector/`


### :package: Have you spent some time checking if this feature request has been raised before?

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

### :package: Have you read the Contributing Guidelines?

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

### :sparkles: Are you willing to submit a PR?


Resolution:
<think>
PR Context:
- Title: refactor(connector): [Klarna] Expand wildcard match arms
- Merged: 2023-10-01T18:24:54Z
- Files changed: 1 files
- Commits: 1 commits

Implementation approach:
## Type of Change

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description

Match arms using the wildcard patten (`_`) can be dangereous when extending enums since developers may miss locations where new variants should be handled. This patch expands all wildcard patterns in the Klarna connector to avoid this problem.

## Motivation and Context

Fixes #2273 

## How did you test it?

`cargo ch
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** refactor(connector): [Klarna] Expand wildcard match arms (#2403)
Files to modify:


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