fixup! fix(exporters): use parseHeaders() to ensure header-values are…

… not 'undefined'

experimental/packages/otlp-exporter-base/test/common/util.test.ts

@@ -46,7 +46,7 @@ describe('utils', () => {
       const args = spyWarn.args[0];
       assert.strictEqual(
         args[0],
-        'Header "foo1" has wrong value and will be ignored'
+        'Header "foo1" has invalid value (undefined) and will be ignored'
       );
     });