[CQ] migrate off deprecated PropertiesComponent.getValues invocations

[pq]

PropertiesComponent.getValues is deprecated in favor of PropertiesComponent.getList.

Verifier output:

      #Deprecated method com.intellij.ide.util.PropertiesComponent.getValues(String) invocation
          Deprecated method com.intellij.ide.util.PropertiesComponent.getValues(java.lang.String arg0) : java.lang.String[] is invoked in io.flutter.sdk.FlutterSdkUtil.updateKnownPaths(String, String) : void
          Deprecated method com.intellij.ide.util.PropertiesComponent.getValues(java.lang.String arg0) : java.lang.String[] is invoked in io.flutter.sdk.FlutterSdkUtil.getKnownFlutterSdkPaths() : String[]

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