[master] Fix utf8 handling in 'pass' renderer and make it more robust

[dmach]

What does this PR do?

Fix utf8 handling in 'pass' renderer and make it more robust

What issues does this PR fix or reference?

Fixes:

Previous Behavior

The pass renderer used Popen() without encoding, hence reading bytes.
The consequent pass_data.rstrip("\r\n") failed on TypeError because of mixing bytes with strings.
This was also due to using mocks in the tests too much.

New Behavior

Popen() specifies utf-8 encoding, therefore no bytes appear in the output.
Tests were extended by calling out to an actualr executable to test Popen() properly.

Using the utf-8 encoding when retrieving secrets from the password store should be ok,
because I was told by the pass developers that the tool is supposed to work with simple text data only.
No binary data (bytes) should be used.

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

Commits signed with GPG?

No

[github-actions]

💔 All backports failed

Status	Branch	Result
❌	3006.x	Backport failed because of merge conflicts You might need to backport the following PRs to 3006.x: - Migrate string formatting in 'pass' renderer to a f-string

Manual backport

To create the backport manually run:

backport --pr 64300

Questions ?

Please refer to the Backport tool documentation and see the Github Action logs for details