[lldb-dap] Remove (or trim) the DAP log on test failures

Whenever a DAP test fails it seems to dump the entire protocol communication log to the output. Can we avoid doing so as it creates noise when looking at test logs?

Question to `lldb-dap` maintainers: Is there some portion of the current log output that's critical to see on CI? How often is seeing the entire communication history useful when debugging test failures?

CC @da-viper @ashgti @walter-erquinigo @JDevlieghere

Start by locating the lldb-dap tests and the code that prints protocol communication when a test fails. Review the existing failure output and determine which diagnostic portion must remain on CI; done means failures no longer dump the entire communication history while preserving useful debugging context.

Written by the indexing model from the issue text.