build(deps): bump third_party/abseil-cpp from `c1e1b47` to `99bb2f6` (#2364)

Bumps [third_party/abseil-cpp](https://github.com/abseil/abseil-cpp) from `c1e1b47` to `99bb2f6`.
- [Release notes](https://github.com/abseil/abseil-cpp/releases)
- [Commits](https://github.com/abseil/abseil-cpp/compare/c1e1b47d989978cde8c5a2a219df425b785a0c47...99bb2f6f106db314fc93fdda3bdeed4005584887)

---
updated-dependencies:
- dependency-name: third_party/abseil-cpp
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/third_party/abseil-cpp b/third_party/abseil-cpp
index c1e1b47..99bb2f6 160000
--- a/third_party/abseil-cpp
+++ b/third_party/abseil-cpp
@@ -1 +1 @@
-Subproject commit c1e1b47d989978cde8c5a2a219df425b785a0c47
+Subproject commit 99bb2f6f106db314fc93fdda3bdeed4005584887