Fix various lint warnings (#4409)

- Remove empty file `ExampleInstrumentedTest.java`.
- Replace deprecated `MigrationTestHelper` constructor call.
- Add reified inline extension methods for `Bundle` and `Intent` to
retrieve `Parcelable` and `Serializable` objects by calling the core
`BundleCompat` and `IntentCompat` methods, to allow shorter syntax and
removing the need to pass the class explicitly.
- Replace deprecated `drawable.setColorFilter()` with simpler
`drawable.setTint()` (uses blend mode `SRC_IN` by default, has the same
effect as `SRC_ATOP` when the source is a color).
- Rename shadowed variables (mostly caught exceptions).
- Remove unnecessary `.orEmpty()` on non-null fields.
- Replace `.size() == 0` with `.isEmpty()`.
- Prevent `NullPointerException` when `account.getDisplayName()` is
`null` in `StatusBaseViewHolder.setDisplayName()`.
- Declare `customEmojis` argument as non-null in
`StatusBaseViewHolder.setDisplayName()` because it calls
`CustomEmojiHelper.emojify()` which now requires it to be non-null.
- Prevent `NullPointerException` when no matching filter is found in
`StatusBaseViewHolder.setupFilterPlaceholder()`.
- Remove deprecated call to `setTargetFragment()` (target fragment is
not used anyway).
- Remove deprecated call to `isUserVisibleHint()` and test if the view
has been destroyed instead.
- Remove some unused imports.
- Remove unnecessary casts.
- Rename arguments to supertype names when a warning is shown.
- Prevent a potential memory leak by clearing the
`toolbarVisibilityDisposable` reference in `onDestroyView()`.

app/src/main/java/com/keylesspalace/tusky/adapter/StatusBaseViewHolder.java

@@ -200,7 +200,7 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
         TouchDelegateHelper.expandTouchSizeToFillRow((ViewGroup) itemView, CollectionsKt.listOfNotNull(replyButton, reblogButton, favouriteButton, bookmarkButton, moreButton));
     }
 
-    protected void setDisplayName(@NonNull String name, @Nullable List<Emoji> customEmojis, @NonNull StatusDisplayOptions statusDisplayOptions) {
+    protected void setDisplayName(@NonNull String name, @NonNull List<Emoji> customEmojis, @NonNull StatusDisplayOptions statusDisplayOptions) {
         CharSequence emojifiedName = CustomEmojiHelper.emojify(
             name, customEmojis, displayName, statusDisplayOptions.animateEmojis()
         );
@@ -790,7 +790,7 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
             if (statusDisplayOptions.mediaPreviewEnabled() && hasPreviewableAttachment(attachments)) {
                 setMediaPreviews(attachments, sensitive, listener, status.isShowingContent(), statusDisplayOptions.useBlurhash());
 
-                if (attachments.size() == 0) {
+                if (attachments.isEmpty()) {
                     hideSensitiveMediaWarning();
                 }
                 // Hide the unused label.
@@ -877,7 +877,14 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
             }
         }
 
-        filteredPlaceholderLabel.setText(itemView.getContext().getString(R.string.status_filter_placeholder_label_format, matchedFilter.getTitle()));
+        final String matchedFilterTitle;
+        if (matchedFilter == null) {
+            matchedFilterTitle = "";
+        } else {
+            matchedFilterTitle = matchedFilter.getTitle();
+        }
+
+        filteredPlaceholderLabel.setText(itemView.getContext().getString(R.string.status_filter_placeholder_label_format, matchedFilterTitle));
         filteredPlaceholderShowButton.setOnClickListener(view -> listener.clearWarningAction(getBindingAdapterPosition()));
     }
 
@@ -1154,7 +1161,7 @@ public abstract class StatusBaseViewHolder extends RecyclerView.ViewHolder {
         final Card card = actionable.getCard();
 
         if (cardViewMode != CardViewMode.NONE &&
-            actionable.getAttachments().size() == 0 &&
+            actionable.getAttachments().isEmpty() &&
             actionable.getPoll() == null &&
             card != null &&
             !TextUtils.isEmpty(card.getUrl()) &&

app/src/main/java/com/keylesspalace/tusky/adapter/StatusDetailedViewHolder.java

@@ -9,13 +9,11 @@ import android.text.method.LinkMovementMethod;
 import android.text.style.DynamicDrawableSpan;
 import android.text.style.ImageSpan;
 import android.view.View;
-import android.widget.Button;
 import android.widget.TextView;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.content.res.AppCompatResources;
-import androidx.appcompat.widget.ViewUtils;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.keylesspalace.tusky.R;
@@ -25,7 +23,6 @@ import com.keylesspalace.tusky.util.CardViewMode;
 import com.keylesspalace.tusky.util.LinkHelper;
 import com.keylesspalace.tusky.util.NoUnderlineURLSpan;
 import com.keylesspalace.tusky.util.StatusDisplayOptions;
-import com.keylesspalace.tusky.util.ViewExtensionsKt;
 import com.keylesspalace.tusky.viewdata.StatusViewData;
 
 import java.text.DateFormat;