[Timebox] Adapt activities to new custom objects

[lucasbordeau]

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Scope & Context

The custom objects are now implemented but we still need to modify activity target so it can be used with custom objects.

Current behavior

Activity targets are currently pointing on either companies or people.

Expected behavior

We want activity targets to point on any custom object record.

For this we would need to implement a solution that can reference a custom object and a record id.

Check :

• ActivityTargetInlineCellEditMode
• useHandleCheckableActivityTargetChange
• useFilteredSearchEntityQuery (wait for new version in https://github.com/twentyhq/twenty/issues/2730)

### Tasks
- [ ] Implement activity target on object metadata id + record id
- [ ] Refacto field context / scope on activities
- [ ] Avoid creating empty activities (see existing issue + PR)