always allow mapped resource attributes, and fix tests

Author: mattsains

src/OpenTelemetry.Exporter.Geneva/Internal/MsgPack/MsgPackTraceExporter.cs

@@ -351,7 +351,7 @@ internal int AppendResourceAttributesToBuffer(byte[] buffer, int cursor)
                 }
             }
 
-            if (this.WithResourceAttributes == null || !this.WithResourceAttributes.Contains(entry.Key))
+            if (!isDedicatedField && (this.WithResourceAttributes == null || !this.WithResourceAttributes.Contains(entry.Key)))
             {
                 continue;
             }

test/OpenTelemetry.Exporter.Geneva.Tests/GenevaTraceExporterTests.cs

@@ -206,6 +206,7 @@ public void GenevaTraceExporter_Serialization_Success(bool hasTableNameMapping,
                     ["cloud.roleVer"] = "9.0.15289.2",
                     ["resourceAndPrepopulated"] = "comes from prepopulated",
                 },
+                WithResourceAttributes = ["resourceAttribute", "resourceAndPrepopulated"],
             };
             if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
             {