fix(text-editor): fixes the formatting buttons when clicked to toggle without text selections

[damienrobson-sage]

Proposed behaviour

The formatting is applied and any newly-added text is formatted in the correct way

Current behaviour

When using the command buttons to format text without any selections present, focus snaps to the text editor but no Bold/Italic formatting appears when text is entered.

Checklist

• Commits follow our style guide
• Related issues linked in commit messages if required
• Screenshots are included in the PR if useful
• All themes are supported if required
• Unit tests added or updated if required
• Playwright automation tests added or updated if required
• Storybook added or updated if required
• Translations added or updated (including creating or amending translation keys table in storybook) if required
• Typescript d.ts file added or updated if required
• Related docs have been updated if required

QA

• Tested in provided StackBlitz sandbox/Storybook
• Add new Playwright test coverage if required
• Carbon implementation matches Design System/designs
• UI Tests GitHub check reviewed if required

Testing instructions

Using the default story, click either the Bold or Italic buttons and then type some text into the editor. The formatting should be applied. Click the button again and then continue typing; no further formatting should be applied.