rebase: bump google.golang.org/grpc from 1.68.1 to 1.69.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.68.1 to 1.69.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.68.1...v1.69.0)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/google.golang.org/grpc/balancer/pickfirst/internal/internal.go

@@ -18,7 +18,18 @@
 // Package internal contains code internal to the pickfirst package.
 package internal
 
-import "math/rand"
+import (
+	rand "math/rand/v2"
+	"time"
+)
 
-// RandShuffle pseudo-randomizes the order of addresses.
-var RandShuffle = rand.Shuffle
+var (
+	// RandShuffle pseudo-randomizes the order of addresses.
+	RandShuffle = rand.Shuffle
+	// TimeAfterFunc allows mocking the timer for testing connection delay
+	// related functionality.
+	TimeAfterFunc = func(d time.Duration, f func()) func() {
+		timer := time.AfterFunc(d, f)
+		return func() { timer.Stop() }
+	}
+)