pnpm detection exception

Nobody has claimed this yet.

I'm seeing the following exception during component detection of a pnpm lock file:

```
##[error]Failed to read pnpm yaml file /__w/1/s/pnpm-lock.yaml
System.Collections.Generic.KeyNotFoundException: The given key '@x/y@link:../Y' was not present in the dictionary.
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
at Microsoft.ComponentDetection.Detectors.Pnpm.Pnpm9Detector.ProcessDependencyList(ISingleFileComponentRecorder singleFileComponentRecorder, Dictionary`2 components, Dictionary`2 dependencies, Boolean isDevelopmentDependency)
at Microsoft.ComponentDetection.Detectors.Pnpm.Pnpm9Detector.ProcessDependencySets(ISingleFileComponentRecorder singleFileComponentRecorder, Dictionary`2 components, PnpmHasDependenciesV9 item)
at Microsoft.ComponentDetection.Detectors.Pnpm.Pnpm9Detector.RecordDependencyGraphFromFile(String yamlFileContent, ISingleFileComponentRecorder singleFileComponentRecorder)
at Microsoft.ComponentDetection.Detectors.Pnpm.PnpmComponentDetectorFactory.OnFileFoundAsync(ProcessRequest processRequest, IDictionary`2 detectorArgs, CancellationToken cancellationToken)
````

I can provide the lock file privately (Teams/email).

Note that detection seems to continue afterwards and does show packages in the summary.

Start in Microsoft.ComponentDetection.Detectors.Pnpm.Pnpm9Detector, especially ProcessDependencyList, and reproduce the exception with a pnpm-lock.yaml containing the reported linked dependency key. Confirm that component detection completes without the KeyNotFoundException and still reports the expected packages.

Written by the indexing model from the issue text.