[TS] Allow deep null values on merge operations

[fabioh8010]

Details

This PR fix the typings related to merge operations to allow setting null to deep properties inside the object. Currently this is blocking several TS PRs. They were fixed on this PR but it got reverted, so I created a separate one.

cc @blazejkustra

Related Issues

Automated Tests

Linked PRs

• [TS migration] Migrate 'BankAccounts.js' lib to TypeScript App#28316
• [No QA][TS migration] Migrate 'CheckForPreviousReportActionID.js' lib to TypeScript App#27652
• [No QA] [TS migration] Migrate 'PersonalDetails.js' lib to TypeScript App#28269
• [HOLD for payment 2023-12-28] [TS migration] Migrate 'PersonalDetailsUtils.js' lib to TypeScript App#24884
• [HOLD for payment 2024-01-26] [TS migration] Migrate 'Policy.js' lib to TypeScript App#24918
• [No QA][TS migration] Migrate 'API.js' & 'Middleware' & 'Authentication.js' & 'Network' lib to TypeScript App#28031

[MonilBhavsar]

I could not find the reason why it was reverted before and what we have done to prevent that. Could you please share some context

[fabioh8010]

@MonilBhavsar This PR was reverted because of this. We took the opportunity of that PR to fix some typings on Onyx related to null values, but as it got reverted we decided to create a separate one with just the fix on the types.

[MonilBhavsar]

Thanks! Looks good to me 👍