The OTLP write handler and the PRW v2 histogram append path were missing
ErrTooOldSample from their error type checks, causing these errors to
fall through to the default case and return HTTP 500 Internal Server Error.
This triggered unnecessary retries in OTLP clients like the Python SDK.
The PRW v1 write handler (line 115) and the PRW v2 sample append path
(line 377) already correctly handle ErrTooOldSample as a 400, and this
change makes the remaining paths consistent.
Also adds ErrTooOldSample to the v1 sample/histogram log checks so
these errors are properly logged instead of silently returned.
Fixes#16645
Signed-off-by: Varun Chawla <varun_6april@hotmail.com>
