fuzz test: Add protobuf validate expression. (#21373)
fuzz test: Add protobuf validate expression. (#21373)

Add a validate expression to test specific protobuf files fixing an
assert.

Signed-off-by: Andre Vehreschild <1ad767c355605fc1e3be747183e42a3e09eb51da@x41-dsec.de>
envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy