fix: allow editing of published collection links

[dcshzj]

Problem

Published collection links do not have a draftBlobId, which causes an error in saving published collection links.

Solution

Breaking Changes

• Yes - this PR contains breaking changes
• No - this PR is backwards compatible

Bug Fixes:

• Use the correct function to update the blob (updateBlobById), as that function handles creating the draftBlobId if it is not present.

Tests

• Create a collection link item within a collection.
• Save changes to the collection link item and publish, make sure the publish button is greyed out and the publish is successful.
• Make another change to the collection link.
• Verify that the success toast message appears with the text "Link updated"

[datadog-opengovsg]

Datadog Report

Branch report: fix/allow-edit-collectionlink
Commit report: 149438e
Test service: isomer-studio

✅ 0 Failed, 257 Passed, 36 Skipped, 51.06s Total Time
➡️ Test Sessions change in coverage: 1 no change

[harishv7]

PR #1000 🎉