fix(material/slider): expand value indicators for long labels

[mnkprs]

M3 slider labels use a fixed, rotated 28px container, so years, larger numbers and formatted values can overflow it. Use a horizontally expanding pill with padding, keep labels on one line, and center the entrance animation beneath the label.

This changes the M3 value-indicator shape, including short labels, while retaining its 28px height and existing colors/typography. M2 retains its rectangular label and caret.

Adds browser regressions for growth and shrinkage, text containment, height and centering on single/range sliders in LTR and RTL, plus five-digit/year-range examples in the dev app.

Validation:

• Four regression cases fail against the original styles and pass with the change.
• Slider Chromium and Firefox tests pass; cross-theme browser checks cover M2, M3, RTL and forced colors.
• Sass compilation, theming unit tests, slider harness tests and the slider dev-app build pass.
• All 178 Chromium test targets pass across Angular Components.
• Full TypeScript lint, style lint, formatting and commit-message checks pass.

Fixes #33606.