CCM-16489: Add letter authoring e2e tests

[andykay-nhs]

Description

Raising draft to check CI pipeline status

for each letter type

• create a new template of the letter type
• upload standard docx. (Im unsure if the template type matters here? the rendered output isn't checked. I did create a spanish translated copy of the standard template but if we're not actually validating the final rendered content then I'm not sure this matters and just the standard one works?)
• validates persisted template data is expected by querying dynamo via templateStorageHelper. (Saw this in the existing pdf-letter e2e tests)
• set printing and postage. (Do we need further e2e tests for different printing and postage types? or is setting the same one okay for this?)
• fill out short and long form preview inputs and update preview
• approve
• confirm approved status of template in template list view

Context

Type of changes

• Refactoring (non-breaking change)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would change existing functionality)
• Bug fix (non-breaking change which fixes an issue)

Checklist

• I am familiar with the contributing guidelines
• I have followed the code style of the project
• I have added tests to cover my changes
• I have updated the documentation accordingly
• This PR is a result of pair or mob programming

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