[PATCH] telemetry: fix JSON string formatter

[Bruce Richardson]

On Thu, May 25, 2023 at 09:20:35AM +0200, David Marchand wrote:
> For large strings, we were incorrectly copying uninitialised data to the
> output buffer.
> Restore previous code.
> 
> Fixes: a515b7204e28 ("telemetry: remove VLA in JSON string formatter")
> 
> Signed-off-by: David Marchand <david.marchand at redhat.com>
> ---
Acked-by: Bruce Richardson <bruce.richardson at intel.com>