fixed bug with mobile-money-uganda

[corneliusyaovi]

Description

Fixed bugs in mobile money uganda. Made redirect url an optional paramater.

Related Issue

Motivation and Context

Users were unable to charge mobile money UG. After review, I identified and fixed the bug causing the error in the payment flow. was also able to update response format to match the update.

How Has This Been Tested?

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [x] Refactor (non-breaking change which improves implementation)
• [ ] Performance (non-breaking change which improves performance. Please add associated performance test and results)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Non-functional change (xml comments/documentation/etc)

Checklist:

• [x] My code follows the code style of this project.
• [x] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [x] All new and existing tests passed.
• [x] My branch follows the naming convention bug-<issue#>-<description> or feature-<issue#>-<description>

@Flutterwave/Corvus97 What do you think about these updates?