Refactor keychain wrapper object (Remove unnecessary promises)

[laumair]

Description

Since keychain methods already return promises, there was no need for them to be wrapped in Promise constructors.

Type of change

• Refactor

How Has This Been Tested?

N/A

Checklist:

• My code follows the style guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• For changes to mobile that include native code (including React Native modules): I have verified that both iOS and Android successfully build in both Debug and Release modes
• For changes to shared: If applicable, I have verified that my changes are implemented correctly in desktop and mobile

[rajivshah3]

👍