Bug in BrowserProvider refresh functionality

Description

The dataset of BrowserProvider should contain only the filtered type of Media objects, as per the override-able implementation here: BrowserProvider#L117

Expected behavior

Similarly, the refresh should fetch the media objects such that the dataset remains filtered depending on the implementation of the subclass.

Actual behavior

But that's not the case, as can be seen from here - BrowserProvider#L145. It considers the complete set of media received in the dataset.

Steps to reproduce

I came upon this bug while unit testing the FilePicker mode of BrowserModel. Here's the corresponding Test Suite - FilePickerModelTest. The corresponding stack trace is:

junit.framework.AssertionFailedError: 
Expected :5
Actual   :7 

	at org.videolan.vlc.viewmodels.browser.FilePickerModelTest.whenRootHasFilesAndRefreshCalled_getUpdatedListOfDirectories(FilePickerModelTest.kt:134)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
	at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
	at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:55)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.robolectric.internal.SandboxTestRunner$2.lambda$evaluate$0(SandboxTestRunner.java:256)
	at org.robolectric.internal.bytecode.Sandbox.lambda$runOnMainThread$0(Sandbox.java:89)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)