Take grpc to 1.83.2 across the nine modules that carry it

GHSA-2v4p-qf9q-27wj is a panic in gRPC-Go's xDS routing interceptor: a
request arriving with neither `:authority` nor `Host` indexes an empty
slice, the per-RPC goroutine does not recover, and the process dies.
High, and nine alerts, because nine go.mod files pin the same version --
eight directly, terraform indirectly.

Nothing here was reachable. The interceptor is installed by
`xds.NewGRPCServer`, which this repo never calls: the one production
server is `grpc.NewServer(grpc.Creds(...))` in ingest/internal/grpcserver
and the only other is a plain one in a searchclient test. That is also
why security-scan has been green throughout -- govulncheck reports on
reachability and found nothing on 1.83.1, while Dependabot reports on
version ranges and found nine. Both were right.

Taken anyway: it is a patch release, and the next advisory in this
dependency may well land somewhere we do reach.

`go mod tidy` carried the indirect requirements grpc 1.83.2 asks for --
x/net, x/text, x/sys and friends. No CI job builds or tests Go here, so
all nine modules were built locally and api, ingest and enterprise
tested with -count=1, since a cached pass would not have exercised the
new version.

The dependabot.yml is the other half. There was no config, so nothing
opened a PR against any of this. Go majors stay out of the group, being
import path changes rather than bumps.

enterprise/go.mod

@@ -37,7 +37,7 @@ require (
 	github.com/jackc/pgx/v5 v5.10.0
 	golang.org/x/oauth2 v0.36.0
 	golang.org/x/sync v0.22.0
-	google.golang.org/grpc v1.83.1
+	google.golang.org/grpc v1.83.2
 	k8s.io/api v0.31.0
 	k8s.io/apimachinery v0.31.0
 	k8s.io/client-go v0.31.0
@@ -88,7 +88,7 @@ require (
 	go.opentelemetry.io/otel v1.44.0 // indirect
 	go.opentelemetry.io/otel/trace v1.44.0 // indirect
 	golang.org/x/crypto v0.55.0 // indirect
-	golang.org/x/net v0.57.0 // indirect
+	golang.org/x/net v0.58.0 // indirect
 	golang.org/x/sys v0.47.0 // indirect
 	golang.org/x/term v0.45.0 // indirect
 	golang.org/x/text v0.41.0 // indirect