Avoid direct modification of HTML

[PiyushChandra17]

Fixes #2174

Changes:

• Stored line number as a state and passed down as a prop in EditorAccessibility component
• Since it is a class-based component, handled React state, componentDidMount, componentWillUnmount and props accordingly
• In future, i guess we are going to convert this into Functional Component where useEffect hook will come into play

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123

[raclim]

This is great, thanks for your work on this!