Issue Type: Bug

1. Configure an exception filter with an invalid condition. In my case, I am using an experimental version of the C# debugger, and I used the bogus coniditon of '==Bogus'
2. Start debugging

Expected:
VS Code should somehow tell me that I entered an invalid exception filter by displaying the text from the error response as the DAP spec indicates. My suggestion would be a warning icon next to the exception filters and display the error message as a notification.

Actual:
The error response isn't displayed anywhere.

Here is a partial protocol trace:

-> {"command":"setExceptionBreakpoints","arguments":{"filters":[],"filterOptions":[{"filterId":"all","condition":"==Bogus"},{"filterId":"user-unhandled"}]},"type":"request","seq":5}
<- {"seq":10,"type":"response","request_seq":5,"success":false,"command":"setExceptionBreakpoints","message":"Syntax error in condition for 'All Exceptions'. Unexpected character near column 0 (character '=')."}

VS Code version: Code - Insiders 1.54.0-insider (3290f9a, 2021-02-26T05:13:29.656Z)
OS version: Windows_NT x64 10.0.19042