internal: generate clients with protoc-gen-go@v1.4.1
internal: generate clients with protoc-gen-go@v1.4.1

This will make go-genproto messages make use of the new
protoreflect features and remove XXX fields. From my testing I
believe this should be safe. The subsequent regen PR/CL will need
some manual tweaks because of diffs in the mod files.

Updates: #1815
Change-Id: Ic9e0029c37bb7557245c68ef37dd1ddca37cbe66
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/56412
Reviewed-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Noah Dietz <892d271bd3cbb39857a7b053afeb6c28a7075b07@google.com>
Reviewed-by: Chris Broadfoot <0c2851a4f8ab4aa5606e69c0757771dd13dbe686@google.com>
Reviewed-by: Tyler Bui-Palsulich <b41e4aa57d2ad7eb1b29835a1b483e209dcc3c0e@google.com>

googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go