CCM-15562: Add campaignId check to update routing config

[m-salaudeen]

Description

The implementation plan in this ticket is to make sure that when letter template update is happening, a check is made to make sure that the campaignId in the template is the same as the campaignId in the routing config.

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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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.

[nicki-nhs]

can you make sure you update the description on the PR please

[nicki-nhs]

fairly confident your tests here https://github.com/NHSDigital/nhs-notify-internal/actions/runs/24780369492 are failing because the campaign IDs in the component and e2e tests dont match between the templates being added and the routing configs they are being added to

The base branch was changed.