fix for bottom adjustment (facebook#46475)

Summary:
Pull Request resolved: facebook#46475

fm.top is negative, so we want to add in order to decrease the absolute value, but fm.bottom is positive, so we need to subtract instead here

Changelog: [internal]

Reviewed By: NickGerleman

Differential Revision: D62612192

fbshipit-source-id: fc942abcb5a1ddedd6547aca66a188736e4ec029

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/text/internal/span/CustomLineHeightSpan.kt

@@ -53,11 +53,11 @@ public class CustomLineHeightSpan(height: Float) : LineHeightSpan, ReactSpan {
 
       // Adjust fm.top and fm.bottom
       fm.top += topReduction
-      fm.bottom += bottomReduction
+      fm.bottom -= bottomReduction
 
       // If there's a remainder, put it on the top
       val remainder = excess - (topReduction + bottomReduction)
-      fm.top += remainder
+      fm.top -= remainder
     } else {
       // Show proportionally additional ascent / top & descent / bottom
       val additional = lineHeight - (-fm.top + fm.bottom)