Add Ubuntu Pro chip to the hero pattern - #5826

Done

• Add chip_text / chip_aria_label params to the vf_hero macro, rendering the branded Ubuntu Pro chip below the subtitle across all hero layouts (50/50, full-width image, 25/75 signpost, 75/25, fallback).
• Scope an 8px chip icon→text gap to the hero (.p-section--hero .p-chip--branded) — the shared .p-chip--branded rule is untouched, so this is non-breaking.
• Add a hero example (hero-with-chip) and document the new params.

Ticket: WD-37738

Based on a request from Lidia to include the new chip component to product pages "connected" to Ubuntu Pro, to raise awareness of everything that is part of the subscription and to have consistent messaging about Pro in relevant pages. We need to roll out the right version of the chip for each of the pages in the spreadsheet, making sure that the design is tasteful and doesn't clash with existing CTAs in the hero section of those pages.

QA

• On this PR's demo build, open the example: /docs/examples/patterns/hero/hero-with-chip.
• Confirm the chip renders below the subtitle (order: title → subtitle → chip → description → CTA) and that the icon→text gap is 8px.
• Confirm existing heroes render unchanged: /docs/examples/patterns/hero/hero-50-50 has no chip.
• Review updated documentation:
  • /docs/patterns/hero — new "With Ubuntu Pro chip" section.

Check if PR is ready for release

• PR label for release notes: Feature 🎁.
• package.json version bumped 4.55.1 → 4.56.0 (minor — new macro params, no existing API changed).
• releases.yml updated with the Hero chip entry.

Screenshots

Design reference (anticipated formats and hero placement across breakpoints) provided in the ticket; the hero-with-chip example reproduces the "Available with Ubuntu Pro" chip below the subtitle.