fix(ui): allow Font Awesome fa-classic in QIcon (fix: #17483)

[mjwlist]

What kind of change does this PR introduce?

• Bugfix
• Feature
• Documentation
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes
• No

The PR fulfills these requirements:

• It's submitted to the dev branch (or v[X] branch)
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix: #xxx[,#xxx], where "xxx" is the issue number)
• It's been tested on a Cordova (iOS, Android) app
• It's been tested on an Electron app
• Any necessary documentation has been added or updated in the docs or explained in the PR's description.

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to start a new feature discussion first and wait for approval before working on it)

Other information:
The valid Font Awesome v6 class 'fa-classic' causes the QIcon component to render incorrectly.

For example:
<q-icon name="fa-classic fa-regular fa-calendar-days" size="5rem" />
Will render:
<i class="q-icon notranslate material-icons" aria-hidden="true" role="presentation" style="font-size: 5rem;">fa-classic fa-regular fa-calendar-days</i>

Without the 'fa-classic' class it will render correctly.

For example:
<q-icon name="fa-regular fa-calendar-days" size="5rem" />
Will render:
<i class="q-icon fa-regular fa-calendar-days" aria-hidden="true" role="presentation" style="font-size: 5rem;"> </i>

This pull request fixes this issue by adding 'classic' to the Font Awsome regex validation in QIcon.
const faRE = /^(fa-(classic|sharp|solid|regular|light|brands|duotone|thin)|[lf]a[srlbdk]?) /

[github-actions]

UI Tests Results

    1 files     98 suites   37s ⏱️
1 031 tests 1 031 ✅ 0 💤 0 ❌
1 050 runs  1 050 ✅ 0 💤 0 ❌

Results for commit 30ff608.

[yusufkandemir]

Thanks for contributing! The fix will be included in quasar v2.16.11.