cli (base): Flush output on self.disp:

When `li` stdout was redirected (e.g. with a pipe), the buffer was preventing to display
immediately data, which is a problem when we need it immediately (like when monitoring
with `li debug monitor`). Flushing is now done immediately to avoid that.

libervia/cli/base.py

@@ -326,9 +326,9 @@ class LiberviaCli:
         """
         if self.verbosity >= verbosity:
             if error:
-                print(msg, end=end, file=sys.stderr)
+                print(msg, end=end, file=sys.stderr, flush=True)
             else:
-                print(msg, end=end)
+                print(msg, end=end, flush=True)
 
     async def output(self, type_, name, extra_outputs, data):
         if name in extra_outputs: