fix: remove gap if its last element in line (fix flex gap extra spacing when children determine parents main axis size) (#1188)

Summary:
Fixes - https://github.com/facebook/react-native/issues/35553

## Approach
We're using `betweenMainDim` to add [gap between](bbeede82d3/yoga/Yoga.cpp (L2495)) items in main axis. This is resulting in increased [main axis](bbeede82d3/yoga/Yoga.cpp (L2598)) dimension of the container as it gets added even for the last element. One solution is to keep using it and subtract the gap when last element is reached.

## Aside
Mutating this value feels weird, but I think `betweenMainDim` gets initialized for every line so should be fine? I did some manual tests to verify. I tried running tests but I'll have to downgrade the java version. Let me know if anything fails. Thanks! 🙏

Pull Request resolved: https://github.com/facebook/yoga/pull/1188

Test Plan: Added fixtures which previously failed but now pass.

Reviewed By: necolas

Differential Revision: D42078162

Pulled By: NickGerleman

fbshipit-source-id: 0e535618350422e001141a8786a83fc81651afe9

yoga/Yoga.cpp

@@ -2540,6 +2540,11 @@ static void YGJustifyMainAxis(
     const YGNodeRef child = node->getChild(i);
     const YGStyle& childStyle = child->getStyle();
     const YGLayout childLayout = child->getLayout();
+    const bool isLastChild = i == collectedFlexItemsValues.endOfLineIndex - 1;
+    // remove the gap if it is the last element of the line
+    if (isLastChild) {
+      betweenMainDim -= gap;
+    }
     if (childStyle.display() == YGDisplayNone) {
       continue;
     }