[iOS] Making Sure that the App Is Properly Signed (MSTG‑CODE‑1)

[sushi2k]

Describe the issue

The test case for "Making Sure that the App Is Properly Signed (MSTG‑CODE‑1)" for iOS is only an overview without much information on what to do with the codesign output.

It should describe what to look out for in codesign output and how to verify that it wasn't modified.

Optional: Testcase or section

Making Sure that the App Is Properly Signed (MSTG‑CODE‑1) in 0x06i

https://github.com/OWASP/owasp-mstg/blob/master/Document/0x06i-Testing-Code-Quality-and-Build-Settings.md#making-sure-that-the-app-is-properly-signed