fix: skip null pointer in EDS validation

Skips gap in LocalityLbEndpoints priorities that caused nullprt
dereference and Envoy crashed with SEGFAULT. Affected when RING_HASH or
MAGLEV loadbalancer policy is used.

Signed-off-by: Pavel Kvasnička <pavel.kvasnicka@firma.seznam.cz>

Author: ctvera

source/extensions/load_balancing_policies/common/thread_aware_lb_impl.cc

@@ -393,6 +393,9 @@ TypedHashLbConfigBase::TypedHashLbConfigBase(absl::Span<const HashPolicyProto* c
 absl::Status TypedHashLbConfigBase::validateEndpoints(const PriorityState& priorities) const {
 
   for (const auto& [hosts, locality_weights_map] : priorities) {
+    if (hosts == nullptr) {
+      continue;
+    }
     // Sum should be at most uint32_t max value, so we can validate it by accumulating into uint64_t
     // and making sure there was no overflow.
     uint64_t host_sum = 0;