[services] refactor some if let statements to reduce nesting

Summary: pretty straightforward refactor. resolves [ENG-1305 : Refactor if let error handling](https://linear.app/comm/issue/ENG-1305/refactor-if-let-error-handling)

Test Plan: cargo build

Reviewers: palys-swm, karol-bisztyga, jimpo

Reviewed By: palys-swm

Subscribers: ashoat, Adrian, atul, yayabosh

Differential Revision: https://phab.comm.dev/D4386