Getting type null on user feed

[sonika-shah]

Affected module
Backend

Describe the bug
When we open the user feed, getting message
An exception with message [Cannot invoke "String.equalsIgnoreCase(String)" because "type" is null] was thrown while processing request.
this is as the thread_entity table contains some of the threads having type null

To Reproduce
Load the user feed page

Screenshots or steps to reproduce

Expected behavior
Should not get the exception

Version:

• OS: [e.g. iOS]
• Python version:
• OpenMetadata version: 1.5.5
• OpenMetadata Ingestion package version: [e.g. openmetadata-ingestion[docker]==XYZ]

Additional context
Add any other context about the problem here.