[CCM-11544] Choose alternative letter formats for a message plan

[nicki-nhs]

• CCM-11544 - Create choose template screens for accessible and language letters
• CCM-11494 - Add alternative letter formats to the 'Choose templates' screen

Description

• Updated arrow icons as per new updated versions in design system
• Updated "choose templates" page to support choosing alternative letter formats
• Support removing multiple templates at once (remove all language templates)
• Created new pages for choose and preview large print and foreign language letter templates for message plans
• Created new components LanguageLetterTemplates, ChooseLanguageLetterTemplates, MessagePlanConditionalTemplates for displaying and selecting conditional templates
• Updated MessagePlanChannelList, MessagePlanBlock to support accessible formats and translations for conditional templates
• Updated ChooseChannelTemplate to support large print
• Added functions to manage conditional templates in cascade items - add, remove, replace, and extract accessible formats and languages
• New Zod validators validateLargePrintLetterTemplate and validateForeignLanguageLetterTemplate to ensure correct template subtypes
• Updated update-routing-config endpoint to handle ConditionalTemplateAccessible and ConditionalTemplateLanguage types
• New playwright tests for choosing and previewing large print and foreign language templates with new page objects
• Updated routing config and template factories to support conditional templates in test data
• Refactored use of back links in pages and tests - consistent use of top and bottom link naming/test IDs etc

Context

Allow users to manage alternative letter formats on their message plan - large print and foreign languages

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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Sensitive Information Declaration

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• I confirm that neither PII/PID nor sensitive data are included in this PR and the codebase changes.