[roll third_party/pigweed] pw_multisink: Remove deprecated GetEntry

Use PopEntry instead of GetEntry.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/59620

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: fad8e85548de5af..505be03e3b3729f
Roller-URL: https://ci.chromium.org/b/8837158704897000465
Cq-Cl-Tag: roller-builder:pigweed-experimental-roller
Cq-Cl-Tag: roller-bid:8837158704897000465
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I46fb902d79ef270248e4e1a81f15257e11680b0c
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/59660
Bot-Commit: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
Commit-Queue: Pigweed Integration Roller <pigweed-integration-roller@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index fad8e85..505be03 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit fad8e85548de5af196c4e824fd37d0f0518c8247
+Subproject commit 505be03e3b3729fe0c184e0c4d20b0cb5dc3ff55