Fix misaligned icons

[pufferfish101007]

Description

Resolves #662 + some additional related bugs

• Vertically align back link icon with text at large font sizes
• Vertically align back breadcrumb icon with text at large font sizes
• Vertically align action link icon with text at large font sizes
• Vertically align pagination icon with text at large font sizes
• Vertically align header 'more' icon with text at large font sizes
• Vertically align radio button with text at large font sizes
• Vertically align checkbox buttons with text at large font sizes
• Vertically align do/don't tick/crosses with text at large font sizes

Checklist

• [ ] Tested against our testing policy (Resolution, Browser & Accessibility)
• [x] Follows our coding standards and style guide
• [x] CHANGELOG entry

Tested on chrome 120, edge 121 & firefox 122 (all on windows). Backstop tests all pass except for the ones that also fail on main.