Hold and Unhold actions in Retention Search should appear to take immediate effect

Steps to reproduce:

• User has at least one Retention Rule available, as well as some documents to attach it to
• User navigates to Retention > Retention search
• User picks filter "Not under legal hold" in the lower panel and clicks on "Legal Hold" (screenshot)
• User types a description and clicks "Legal Hold"

Expected behaviour:

• Legal Hold confirmation dialog closes
• There is a notification that the document is under Legal Hold - "Legal hold set"  
• User can immediately confirm the document is under Legal Hold.

Actual behaviour:

• Legal Hold confirmation dialog doesn't close
• There is only a notification that reads "Setting Legal Hold"
• User can only confirm the document is under legal hold after refreshing the page.

Although the Unhold action doesn't involve a confirmation dialog, it also has the issue of having to refresh the page to confirm the document is no longer under legal hold.