internal/proxy: don't report NotFound errors

Change-Id: Ia1e93c0a9861a0de0176c485c69c7a312ade4abf
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/347557
Trust: Jonathan Amsterdam <jba@google.com>
Run-TryBot: Jonathan Amsterdam <jba@google.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Julie Qiu <julie@golang.org>
diff --git a/internal/proxy/client.go b/internal/proxy/client.go
index 17f4f7b..dfd7179 100644
--- a/internal/proxy/client.go
+++ b/internal/proxy/client.go
@@ -93,7 +93,7 @@
 		// an uncached module when fetch is disabled.
 		// Don't report timeouts, because they are relatively frequent and not actionable.
 		wrap := derrors.Wrap
-		if !errors.Is(err, derrors.NotFetched) && !errors.Is(err, derrors.ProxyTimedOut) {
+		if !errors.Is(err, derrors.NotFetched) && !errors.Is(err, derrors.ProxyTimedOut) && !errors.Is(err, derrors.NotFound) {
 			wrap = derrors.WrapAndReport
 		}
 		wrap(&err, "proxy.Client.Info(%q, %q)", modulePath, requestedVersion)