Fix JS validation for word count in textarea

[DaniBitZesty]

📝 A short description of the changes

• When text is pasted into textareas, spaces are converted to non-breaking spaces ( ) and line breaks to (\n), previous code was counting words by spaces and ignoring these.
• Also, step validation was not working on these questions, this PR changes use of .context to .find('textarea') instead, which correctly identifies the textarea element in both validate and validateStep functions

🔗 Link to the relevant story (or stories)

• https://app.asana.com/0/1200504523179345/1207796563026166/f#:~:text=%5BKAEIMP0724%5D%20Update%20validations%20on%20text%20fields%20with%20word%20counts/limits

Deployment implications

✅ Checklist

• Features that cannot go live are behind a feature flag/env var or specify deploy date and open PR as draft
• I have checked that commit messages make sense and explain the reasoning for each change
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have squashed any unnecessary or part-finished commits

🖼️ Screenshots (if appropriate - no PII/Prod data):