fix(users/Profpatsch/whatcd-resolver): pretty AppException

AppException would be a console-pretty-printed version for http
errors, which would print all the escape codes in the jaeger traces of
the exception, making it more-or-less unreadable.

So instead, let’s make AppException two cases, an ErrorTree case which
is printed as-is (no color), and a “Pretty” case which is printed
using the pretty module (colors on console, no colors in otel).

Somewhat involved, I guess this is temporary until I figure out what
is really needed.

Change-Id: Iff4a8651c5f5368a5b798541efc19cc7ab9de34b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12232
Reviewed-by: Profpatsch <mail@profpatsch.de>
Tested-by: BuildkiteCI

users/Profpatsch/openlab-tools/src/OpenlabTools.hs

@@ -389,7 +389,7 @@ httpJson opts span parser req = do
             | statusCode == 200,
               Nothing <- contentType ->
                 Left [fmt|Server returned a body with unspecified content type|]
-            | code <- statusCode -> Left [fmt|Server returned an non-200 error code, code {code}: {resp & showPretty}|]
+            | code <- statusCode -> Left $ singleError [fmt|Server returned an non-200 error code, code {code}: {[pretty resp] & prettyErrsNoColor}|]
       )
     >>= assertM
       span