Getting ESBuild, Lit, and Storybook to all agree on how to read and parse stylesheets is a serious
pain. This fix better identifies the value types (instances) being passed from various sources in
the repo to the three *different* kinds of style processors we're using (the native one, the
polyfill one, and whatever the heck Storybook does internally).

Falling back to using older CSS instantiating techniques one era at a time seems to do the trick.
It's ugly, but in the face of the aggressive styling we use to avoid Flashes of Unstyled Content
(FLoUC), it's the logic with which we're left.

In standard mode, the following warning appears on the console when running a Flow:

```
Autofocus processing was blocked because a document already has a focused element.
```

In compatibility mode, the following **error** appears on the console when running a Flow:

```
crawler-inject.js:1106 Uncaught TypeError: Failed to execute 'observe' on 'MutationObserver': parameter 1 is not of type 'Node'.
    at initDomMutationObservers (crawler-inject.js:1106:18)
    at crawler-inject.js:1114:24
    at Array.forEach (<anonymous>)
    at initDomMutationObservers (crawler-inject.js:1114:10)
    at crawler-inject.js:1549:1
initDomMutationObservers @ crawler-inject.js:1106
(anonymous) @ crawler-inject.js:1114
initDomMutationObservers @ crawler-inject.js:1114
(anonymous) @ crawler-inject.js:1549
```

Despite this error, nothing seems to be broken and flows work as anticipated.

#8890)

The PFSizes enum is used by more than just the Spinner, but has been left inside the Spinner for all
this time, making refactoring the Spinner for Patternfly 5 a little harder (okay, an annoying amount
harder) than it should be.

This commit moves this UI-specific, widely-use enum into its own folder in `common`, and refactors
everything else to use it.  As is often the case, the refactor is mechanical:

```
perl -pi.bak -e 's{import \{ PFSize \} from "\@goauthentik/elements/Spinner";}{import \{ PFSize \}
from "\@goauthentik/common/enums.js";}' \\
    $(rg -l 'import.*PFSize')
```

**Note:** This commit is dependent upon the ["clean up and remove redundant alias `@goauthentik/app`" PR](#8889)