Re-enable gtest absl pretty printers.

After https://webrtc-review.googlesource.com/c/src/+/93733, WebRTC
should be able to use absl pretty printers again.

Bug: None
Change-Id: I1ea63707e59ad502e40df84ca0abb03054d25106
Reviewed-on: https://webrtc-review.googlesource.com/93741
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24272}

.gn

@@ -80,5 +80,5 @@ default_args = {
   # for unittests, it can be disabled (see third_party/libyuv/BUILD.gn)
   libyuv_use_gflags = false
 
-  gtest_enable_absl_printers = false
+  gtest_enable_absl_printers = true
 }