Brew updates halted by outdated Xcode version on Macos11 machines

Brew update wants Xcode to be updated to >= 13.2.1 to be able to perform updates on installed packages.

```
test-macstadium-macos11-arm64-1

"msg": "Warning: You are using macOS 11.\nWe (and Apple) do not provide support for this old version.\n
It is expected behaviour that some formulae will fail to build in this old version.\nIt is expected behaviour that Homebrew will be buggy and slow.\nDo not create any issues about this on Homebrew's GitHub repositories.\n
Do not create any issues even if you think this message is unrelated.\nAny opened issues will be immediately closed without response.\nDo not ask for help from Homebrew or its maintainers on social media.\n
You may ask for help in Homebrew's discussions but are unlikely to receive a response.\n
Try to figure out the problem yourself and submit a fix as a pull request.\nWe will review it but may or may not accept it.\n
\nError: Your Xcode (11.7 => /Applications/Xcode-11.7.app/Xcode.app/Contents/Developer) is too outdated.\n
Please update to Xcode 13.2.1 (or delete it).\nXcode can be updated from the App Store.\n
\nError: Your Command Line Tools are too outdated.\nUpdate them from Software Update in System Preferences.\n
\nIf that doesn't show you any updates, run:\n
sudo rm -rf /Library/Developer/CommandLineTools\n sudo xcode-select --install\n\nAlternatively, manually download them from:\n https://developer.apple.com/download/all/.\nYou should download the Command Line Tools for Xcode 13.2.1.",
```

```
build-macstadium-macos11-arm64-1

"msg": "Warning: You are using macOS 11.\nWe (and Apple) do not provide support for this old version.\n
It is expected behaviour that some formulae will fail to build in this old version.\n
It is expected behaviour that Homebrew will be buggy and slow.\nDo not create any issues about this on Homebrew's GitHub repositories.\n
Do not create any issues even if you think this message is unrelated.\nAny opened issues will be immediately closed without response.\nDo not ask for help from Homebrew or its maintainers on social media.\n
You may ask for help in Homebrew's discussions but are unlikely to receive a response.\n
Try to figure out the problem yourself and submit a fix as a pull request.\nWe will review it but may or may not accept it.\n\nError: Your Command Line Tools are too outdated.\n
Update them from Software Update in System Preferences.\n\nIf that doesn't show you any updates, run:\n
sudo rm -rf /Library/Developer/CommandLineTools\n sudo xcode-select --install\n
\nAlternatively, manually download them from:\n https://developer.apple.com/download/all/.\n
You should download the Command Line Tools for Xcode 13.2.1.",
```

Two separate but similar error logs. The first suggests we need to add something to the macos part of the playbooks which switch xcode back to command line tools before running any macos ansible tasks. The second error log recommends updating command line tools' xcode to >= 13.2.1

Start by reviewing the macOS portion of the Ansible playbooks and the two supplied MacStadium error logs. Reproduce the brew update failure on the affected machines, then verify that the playbooks handle Xcode and Command Line Tools at version 13.2.1 or newer and that both update paths complete successfully.

Written by the indexing model from the issue text.