If no certificates are found on server lookup then we show "No certificates found", but NVDA doesn't announce this result.

How to reproduce:

• Open Lookup on Server
• Enter an email address that won't give any results
• Press Enter or click the Search button

Observed:

• The empty result table has keyboard focus
• The result table is overlaid with a text overlay stating "No certificates found" - OK
• NVDA reads "Results tree view" - Not OK

Expected:

• The result table is overlaid with a text overlay stating "No certificates found"
• NVDA reads "No certificates found"