[master] fix(mac_brew_pkg): Improve search for Homebrew's prefix

[cdalvaro]

What does this PR do?

This PR improves the way salt tries to figure out the brew macOS command.

What issues does this PR fix or reference?

After latest changes in brew command: Homebrew/brew#15787, Homebrew/brew#15818 and finally Homebrew/brew#15827, salt fails executing brew commands when no HOME env variable is set with the following error:

[salt.state       :325 ][ERROR   ][9799] An error was encountered while removing package(s): Path not found: Error: $HOME must be set to run brew./bin/brew
[salt.loaded.int.module.cmdmod:920 ][ERROR   ][13361] Command 'brew' failed with return code: 1

This is due because salt-minion is launched as a Launch Daemon in macOS with a very reduced environment:

LC_PAPER=C
LC_ADDRESS=C
LC_MONETARY=C
LC_NUMERIC=C
LC_TELEPHONE=C
PATH=/opt/homebrew/bin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
LC_MESSAGES=C
LC_IDENTIFICATION=C
LC_COLLATE=C
PWD=/private/var/root
LC_MEASUREMENT=C
XPC_FLAGS=0x0
XPC_SERVICE_NAME=0
SHLVL=1
LANGUAGE=C
HOMEBREW_PREFIX=/opt/homebrew
LC_CTYPE=C
LC_TIME=C
LC_NAME=C
_=/usr/bin/env

(I have added PATH and HOMEBREW_PREFIX manually to my daemon's plist file)

When salt tries to recover the brew --prefix with the following code:

salt/salt/modules/mac_brew_pkg.py

Lines 96 to 102 in 4e8b77d

	def _homebrew_bin():
	"""
	Returns the full path to the homebrew binary in the PATH
	"""
	ret = __salt__["cmd.run"]("brew --prefix", output_loglevel="trace")
	ret += "/bin/brew"
	return ret

There is no $HOME, neither $USER, neither $LOGNAME in the environment.

This PR tries to figure out the Homebrew's prefix, by using the HOMEBREW_PREFIX env variable. As it is already used in other salt modules, like in rsax931.py:

salt/salt/utils/rsax931.py

Line 41 in 4e8b77d

brew_prefix = os.getenv("HOMEBREW_PREFIX", "/usr/local")

If the environment variable is not set, then it tries the most common paths for brew regarding the system architecture. /opt/homebrew for Apple Silicon (a.k.a.: arm64), /usr/local for Intel Macs (a.k.a.: x86_64).

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?

Yes

Closes #61340