Remove left over code from deprecating Android < 21 (#30243)

Summary:
Came to learn RN is deprecating Android 19, 20: a17ff44

Did a quick check of left over code from the deprecation.

## Changelog

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https://github.com/facebook/react-native/wiki/Changelog
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[Android] [Deprecated] - Cleanup usages of deprecated Android API

Pull Request resolved: #30243

Reviewed By: fkgozali

Differential Revision: D24548084

Pulled By: JoshuaGross

fbshipit-source-id: 3054ca1455bcff2bd5c9791633942dc0cca7cb2c

ReactAndroid/src/main/java/com/facebook/react/bridge/queue/ReactQueueConfigurationSpec.java

@@ -19,8 +19,6 @@
  */
 public class ReactQueueConfigurationSpec {
 
-  private static final long LEGACY_STACK_SIZE_BYTES = 2000000;
-
   private final MessageQueueThreadSpec mNativeModulesQueueThreadSpec;
   private final MessageQueueThreadSpec mJSQueueThreadSpec;
 
@@ -44,11 +42,7 @@ public static Builder builder() {
   }
 
   public static ReactQueueConfigurationSpec createDefault() {
-    MessageQueueThreadSpec spec =
-        Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP
-            ? MessageQueueThreadSpec.newBackgroundThreadSpec(
-                "native_modules", LEGACY_STACK_SIZE_BYTES)
-            : MessageQueueThreadSpec.newBackgroundThreadSpec("native_modules");
+    MessageQueueThreadSpec spec = MessageQueueThreadSpec.newBackgroundThreadSpec("native_modules");
     return builder()
         .setJSQueueThreadSpec(MessageQueueThreadSpec.newBackgroundThreadSpec("js"))
         .setNativeModulesQueueThreadSpec(spec)

ReactAndroid/src/main/java/com/facebook/react/modules/datepicker/DismissableDatePickerDialog.java

@@ -17,12 +17,6 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 
-/**
- * Certain versions of Android (Jellybean-KitKat) have a bug where when dismissed, the {@link
- * DatePickerDialog} still calls the OnDateSetListener. This class works around that issue.
- *
- * <p>See: <a href="https://code.google.com/p/android/issues/detail?id=34833">Issue 34833</a>
- */
 public class DismissableDatePickerDialog extends DatePickerDialog {
 
   public DismissableDatePickerDialog(
@@ -46,13 +40,6 @@ public DismissableDatePickerDialog(
     fixSpinner(context, year, monthOfYear, dayOfMonth);
   }
 
-  @Override
-  protected void onStop() {
-    // do *not* call super.onStop() on KitKat on lower, as that would erroneously call the
-    // OnDateSetListener when the dialog is dismissed, or call it twice when "OK" is pressed.
-    super.onStop();
-  }
-
   private void fixSpinner(Context context, int year, int month, int dayOfMonth) {
     if (Build.VERSION.SDK_INT == Build.VERSION_CODES.N) {
       try {

ReactAndroid/src/main/java/com/facebook/react/modules/network/ForwardingCookieHandler.java

@@ -126,7 +126,7 @@ protected void doInBackgroundGuarded(Void... params) {
   }
 
   /**
-   * Instantiating CookieManager in KitKat+ will load the Chromium task taking a 100ish ms so we do
+   * Instantiating CookieManager will load the Chromium task taking a 100ish ms so we do
    * it lazily to make sure it's done on a background thread as needed.
    */
   private @Nullable CookieManager getCookieManager() {

ReactAndroid/src/main/java/com/facebook/react/views/view/ReactDrawableHelper.java

@@ -73,11 +73,7 @@ private static Drawable getDefaultThemeDrawable(Context context) {
   }
 
   private static RippleDrawable getRippleDrawable(
-      Context context, ReadableMap drawableDescriptionDict) {
-    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
-      throw new JSApplicationIllegalArgumentException(
-          "Ripple drawable is not available on android API <21");
-    }
+    Context context, ReadableMap drawableDescriptionDict) {
     int color = getColor(context, drawableDescriptionDict);
     Drawable mask = getMask(drawableDescriptionDict);
     ColorStateList colorStateList =