[clap-v3-utils] Add functions to parse directly from `SignerSource`

[samkim-crypto]

Problem

Summary of Changes

Fixes #

[codecov[bot]]

Codecov Report

Attention: 83 lines in your changes are missing coverage. Please review.

Comparison is base (f9bfb60) 81.7% compared to head (7b3f85b) 81.7%.

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #34678     +/-   ##
=========================================
- Coverage    81.7%    81.7%   -0.1%     
=========================================
  Files         826      826             
  Lines      223371   223411     +40     
=========================================
+ Hits       182578   182588     +10     
- Misses      40793    40823     +30     

[mergify[bot]]

Backports to the beta branch are to be avoided unless absolutely necessary for fixing bugs, security issues, and perf regressions. Changes intended for backport should be structured such that a minimum effective diff can be committed separately from any refactoring, plumbing, cleanup, etc that are not strictly necessary to achieve the goal. Any of the latter should go only into master and ride the normal stabilization schedule. Exceptions include CI/metrics changes, CLI improvements and documentation updates on a case by case basis.