fix(NODE-7073): dont add duplicate metadata

Author: durran

src/mongo_client.ts

@@ -492,6 +492,11 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> implements
    * @param driverInfo - Information about the application or library.
    */
   appendMetadata(driverInfo: DriverInfo) {
+    for (const info of this.options.additionalDriverInfo) {
+      if (info.name === driverInfo.name) {
+        return;
+      }
+    }
     this.options.additionalDriverInfo.push(driverInfo);
     this.options.metadata = makeClientMetadata(this.options);
     this.options.extendedMetadata = addContainerMetadata(this.options.metadata)

test/integration/mongodb-handshake/mongodb-handshake.prose.test.ts

@@ -355,6 +355,13 @@ describe('Client Metadata Update Prose Tests', function () {
           // (Note os is the only one getting set in these tests)
           expect(updatedClientMetadata.os).to.deep.equal(initialClientMetadata.os);
         });
+
+        it('does not append duplicate metadata for the same name', async function () {
+          client.appendMetadata({ name, version, platform });
+          client.appendMetadata({ name, version, platform });
+          await client.db('test').command({ ping: 1 });
+          expect(updatedClientMetadata.driver.name).to.not.contain('|framework|framework');
+        });
       });
     }
   });