ext_proc: Deflak the inactive test (envoyproxy#35240)

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Signed-off-by: tyxia <tyxia@google.com>

test/extensions/filters/http/ext_proc/ext_proc_integration_test.cc

@@ -4409,7 +4409,8 @@ TEST_P(ExtProcIntegrationTest, GetAndSetHeadersUpstreamObservabilityMode) {
   verifyDownstreamResponse(*response, 200);
 }
 
-TEST_P(ExtProcIntegrationTest, GetAndSetHeadersUpstreamObservabilityModeWithLogging) {
+// Upstream filter chain is in alpha mode and it is not actively used in ext_proc at the moment.
+TEST_P(ExtProcIntegrationTest, DISABLED_GetAndSetHeadersUpstreamObservabilityModeWithLogging) {
   proto_config_.set_observability_mode(true);
 
   ConfigOptions config_option = {};