refactor: modernize non standard components to the latest MD3 spec

[MrMuzyk]

Motivation

Modernizes the remaining non-standard components — Avatar, Banner, and DataTable — to the latest MD3 spec by adopting the recently added theme tokens (shape, motion, typography, colors).

Changes

Avatar (AvatarIcon, AvatarText, AvatarImage, new utils.ts)

• Colors: default primary + getContrastingColor(white) → MD3 container pair primaryContainer / onPrimaryContainer. Custom backgrounds keep the getContrastingColor
• luminance fallback (arbitrary per-user colors have no on- role).
• Shape: borderRadius: size / 2 → cornerFull (9999) from src/theme/tokens/sys/shape.
• Typography: AvatarText spreads theme.fonts.titleMedium (family/weight/letterSpacing) before its proportional fontSize/lineHeight.
• Structure: new src/components/Avatar/utils.ts (DEFAULT_SIZE = 64, ICON_SIZE_RATIO = 0.6, resolveAvatarColors) shared by the three files; removes the duplicated
• defaultSize constant.

Banner (Banner.tsx)

• Motion: durations 250 * scale / 200 * scale → theme.motion.duration.medium1 / short4 (values unchanged), plus easing: Easing.bezier(...theme.motion.easing.standard). Dropped the legacy * scale multiplier to match how Switch/Checkbox adopted motion tokens.
• Icon size: size={40} → const ICON_SIZE = 40.

DataTable (DataTableTitle, DataTableCell, DataTablePagination)

• Typography: header → variant="labelMedium" (keeps 12px; lineHeight: 24 retained to stay vertically aligned with the 24dp sort icon); cell → variant="bodyMedium"; pagination labels → variant="bodySmall".
• Motion: sort-arrow spin duration: 150 → theme.motion.duration.short3 (unchanged value) + easing.standard.

Visual / behavioral changes (no public API changed)

• Avatar's default tone flips from solid primary + white content to the primaryContainer / onPrimaryContainer pair.
• Banner & DataTable animations now use the MD3 standard easing curve (was RN's default ease-in-out); Banner no longer scales its duration by theme.animation.scale.
• DataTable header gains MD3 label tracking (letterSpacing: 0.5).

Related issue

#4990

Test plan

• yarn typescript
• yarn lint
• yarn test
• Visual verification (yarn example web):
  • Avatar — Icon/Text/Image render circular with the new tonal default; custom-colored avatars stay legible
  • Banner — show/hide animates correctly via the FAB toggle
  • DataTable — column title sits vertically centered with the sort icon, cell/pagination text reads well, sort arrow still animates on header press

banner.mp4