Cap selection indices when text changes (facebook#26680)

Summary:
This PR facebook#22723 cached selections, so if you had a cached selection indicies, but updated the text to be an empty string, then this would crash.

As reported in facebook#25265 and other issues of `setSpan(4 ... 4) ends beyond length`

## Changelog

[Android] [fixed] - Crash in TextInput
Pull Request resolved: facebook#26680

Test Plan:
```
input.setNativeProps({ text: "xxx", selection: {"begin": 0, "end": 3}});
input.setNativeProps({ text: ""});
```

Differential Revision: D18189703

Pulled By: cpojer

fbshipit-source-id: 67d9615a863fd22598be8d6d4553dec5ac8837ed

Author: MarcoPolo

ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextInputShadowNode.java

@@ -156,6 +156,18 @@ public void setMostRecentEventCount(int mostRecentEventCount) {
   @ReactProp(name = PROP_TEXT)
   public void setText(@Nullable String text) {
     mText = text;
+    if (text != null) {
+      // The selection shouldn't be bigger than the length of the text
+      if (mSelectionStart > text.length()) {
+        mSelectionStart = text.length();
+      }
+      if (mSelectionEnd > text.length()) {
+        mSelectionEnd = text.length();
+      }
+    } else {
+      mSelectionStart = UNSET;
+      mSelectionEnd = UNSET;
+    }
     markUpdated();
   }