Remove redundant use of keyword explicit on QuicConnectionIdHasher default constructor

gfe-relnote: n/a, no behavior change
PiperOrigin-RevId: 258857446
Change-Id: Id746a5a7f72b163738f8bec029aee5d3d8f24f1a

quic/core/quic_connection_id.cc

diff --git a/quic/core/quic_connection_id.cc b/quic/core/quic_connection_id.cc
index f446ac8..c560bcc 100644
--- a/quic/core/quic_connection_id.cc
+++ b/quic/core/quic_connection_id.cc
@@ -32,7 +32,7 @@
 // that they always land in the same hash bucket.
 class QuicConnectionIdHasher {
  public:
-  explicit inline QuicConnectionIdHasher()
+  inline QuicConnectionIdHasher()
       : QuicConnectionIdHasher(QuicRandom::GetInstance()) {}
 
   explicit inline QuicConnectionIdHasher(QuicRandom* random) {