Bugfix: Avoid crash with ResizeableSplit. (#1025)

Component
---------
- Bugfix: Fix a crash with ResizeableSplit. See #1023.
  - Clamp screen size to terminal size.
  - Disallow `ResizeableSplit` with negative size.

Dom
---
- Bugfix: Disallow specifying a negative size constraint. See #1023.

Bug: https://github.com/ArthurSonzogni/FTXUI/issues/1023

src/ftxui/dom/size.cpp

@@ -19,7 +19,7 @@ class Size : public Node {
       : Node(unpack(std::move(child))),
         direction_(direction),
         constraint_(constraint),
-        value_(value) {}
+        value_(std::max(0, value)) {}
 
   void ComputeRequirement() override {
     Node::ComputeRequirement();