Change 'end of form' to 'end of the form'

[hannahkc]

What problem does this pull request solve?

This changes:

• 'end of form' to 'the end of the form' where it's part of a sentence
• 'End of form' to 'End of the form' where it's a fragment

This is for style, consistency and readability.

Trello card:https://trello.com/c/JciJ9SsL/3549-card-in-progress-correct-end-of-form-to-end-of-the-form-or-the-end-of-the-form-as-relevant

Things to consider when reviewing

• I can't run this locally so I hope it all looks ok! I will be checking in the review apps!
• I hope I have caught all the tests etc...
• I haven't been able to squash these commits as it turns out I can't have github desktop on my new computer. Sorry about that! If someone can easily do that for me (I think that's possible?), that would be super!
• Ensure that you consider the wider context.
• Does it work when run on your machine?
• Is it clear what the code is doing?
• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Do the end to end tests need updating before these changes will pass?
• Has all relevant documentation been updated?

[github-actions]

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