Improve text measurement for multiline TextInput on iOS (facebook#49711)

Summary:
Pull Request resolved: facebook#49711

Changelog: [IOS][CHANGED] - Moved workaround for multiline text measurement with `maximumNumberOfLines` earlier in the pipeline

Reviewed By: huntie

Differential Revision: D70314397

fbshipit-source-id: ef7dbf0c4bb3d5053328d81b7d5b8208e92ee7f5

Author: j-piasecki

packages/react-native/ReactCommon/react/renderer/textlayoutmanager/platform/ios/react/renderer/textlayoutmanager/RCTTextLayoutManager.mm

@@ -48,6 +48,18 @@ - (TextMeasurement)measureNSAttributedString:(NSAttributedString *)attributedStr
 
   CGSize maximumSize = CGSize{layoutConstraints.maximumSize.width, CGFLOAT_MAX};
 
+  // A workaround for the issue with empty line measurement:
+  // When maximumNumberOfLines is set to N and N+1 line is empty, the returned
+  // measurement is for N+1 lines. Adding any character to that line results
+  // in the correct measurement.
+  if (paragraphAttributes.maximumNumberOfLines > 0 && attributedString.length > 0 &&
+      [[attributedString string] characterAtIndex:attributedString.length - 1] == '\n') {
+    NSMutableAttributedString *mutableString =
+        [[NSMutableAttributedString alloc] initWithAttributedString:attributedString];
+    [mutableString replaceCharactersInRange:NSMakeRange(attributedString.length - 1, 1) withString:@"\n "];
+    attributedString = mutableString;
+  }
+
   NSTextStorage *textStorage = [self _textStorageAndLayoutManagerWithAttributesString:attributedString
                                                                   paragraphAttributes:paragraphAttributes
                                                                                  size:maximumSize];
@@ -232,17 +244,6 @@ - (NSTextStorage *)_textStorageAndLayoutManagerWithAttributesString:(NSAttribute
   layoutManager.usesFontLeading = NO;
   [layoutManager addTextContainer:textContainer];
 
-  // A workaround for the issue with empty line measurement:
-  // When maximumNumberOfLines is set to N and N+1 line is empty, the returned
-  // measurement is for N+1 lines. Adding any character to that line results
-  // in the correct measurement.
-  if (attributedString.length > 0 && [[attributedString string] characterAtIndex:attributedString.length - 1] == '\n') {
-    NSMutableAttributedString *mutableString =
-        [[NSMutableAttributedString alloc] initWithAttributedString:attributedString];
-    [mutableString replaceCharactersInRange:NSMakeRange(attributedString.length - 1, 1) withString:@"\n "];
-    attributedString = mutableString;
-  }
-
   NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:attributedString];
 
   RCTApplyBaselineOffset(textStorage);