BUG: append_from props should be a list

[gmatthews20]

Change props to the required type of List
Update tests

Description:

props param in append_from is a List, update email workflows and tests to match this

Special Notes:

---

Submitter:

Have you (where applicable):

• Added unit tests?
• Checked the latest commit runs on Dev?
• Updated the example config file(s) and README?

---

Reviewer

Does this PR:

• Place non-StackStorm code into the lib directory?
• Have unit tests for the action/sensor and lib layers?
• Have clear and obvious action parameter names and descriptions?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.20%. Comparing base (2468e98) to head (6c7a0f9).
Report is 61 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #261   +/-   ##
=======================================
  Coverage   98.20%   98.20%           
=======================================
  Files         195      195           
  Lines        7636     7636           
  Branches      460      460           
=======================================
  Hits         7499     7499           
  Misses        110      110           
  Partials       27       27           

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