feat(): add mtls configurations for certs

Author: sandy2008

test/OpenTelemetry.Exporter.OpenTelemetryProtocol.Tests/OtlpSpecConfigDefinitionsTests.cs

@@ -38,7 +38,7 @@ public void AllEnvironmentVariableNames_AreUnique()
         };
 
         var uniqueVars = envVars.Distinct().ToArray();
-        
+
         Assert.Equal(envVars.Length, uniqueVars.Length);
     }