fix: Corrected Typographical Errors in Documentation Files

[cypherpepe]

This pull request addresses several typographical errors found in multiple documentation files. The corrections improve clarity and readability, ensuring a better user experience for developers and readers of the documentation.

Changes Made

1. identity/introduction/background.mdx

   • Corrected redundant "of of" to "of".
     
     

2. identity/tutorials/simple-workflow.mdx

   • Fixed "conviniently" to "conveniently".
   • Corrected "authroize" to "authorize".

3. identity/tutorials/use-nebra-upa.mdx

   • Corrected "retrive" to "retrieve".