UserExperience/AdminBarRemoval: various improvements

[jrfnl]

UserExperience/AdminBarRemoval: add additional tests

• Testing against false positives for calls to methods or namespaced function calls (= the issue being addressed in this PR).
• Safeguarding that function calls using PHP 5.6+ argument unpacking are flagged.
• Safeguarding handling of PHP 8.0+ attribute class using the same name as a target function.
• Safeguarding that the function is not flagged when used as a PHP 8.1+ first class callable.
• Adding tests with more variations:
  • Non-lowercase function call(s).
  • Fully qualified function calls for the escaping functions.
  • Use PHP 7.3+ trailing comma's in a few function calls.
  • Text strings using single quotes and double quotes.

UserExperience/AdminBarRemoval: bug fix - disregard comments in parameter values

The PHPCSUtils PassedParameters::getParameters() return value includes a 'clean' array index, which contains the contents of the parameter stripped of surrounding whitespace and comments.

The AdminBarRemoval sniff uses the parameter contents in a couple of places to compare against a specific text string, but would break if the parameter value would contain a comment.

Fixed now. Includes tests.

UserExperience/AdminBarRemoval: add support for handling PHP 8.0+ function calls using named parameters

Includes tests.

UserExperience/AdminBarRemoval: bug fix - recognize add_action() as alias

... for add_filter().

Includes test.

UserExperience/AdminBarRemoval: add support for recognizing PHP 8.1+ first class callables

... when used as the $callback parameter for add_filter()/add_action().

Includes tests.

UserExperience/AdminBarRemoval: bug fix - function names are case-insensitive

... even when passed as callbacks.

Includes test.

UserExperience/AdminBarRemoval: remove some redundant logic

No need for a switch here.

UserExperience/AdminBarRemoval: bug fix - CSS file might be handled as PHP file

A number of IDEs will use STDIN to run PHPCS and will pass the stdin_path to PHPCS to set the file name, which often results in the filename being quoted.

In that case, the original logic in this sniff would break as the $file_extension would end up being 'css"', which doesn't match the expected 'css'.

The new PHPCSUtils 1.1.0 FilePath::getName() method will strip quotes from the file name, as well as normalize the slashes to forward (*nix) slashes.

Applying that method fixes the bug.

UserExperience/AdminBarRemoval: minor simplification

Let PHP sort out splitting the extension off the file name.