Post Type Fix

Before:
ID: 508 | Type: []
ID: 507 | Type: []
ID: 506 | Type: [article]
ID: 505 | Type: [link]
ID: 504 | Type: [link]

Updated empty types to NULL.

After:
ID: 508 | Type: []
ID: 507 | Type: []
ID: 506 | Type: [article]
ID: 505 | Type: [link]
ID: 504 | Type: [link]