React specific typings for css position (#15575)

* React CSSProperties position made specific

* Add test for css position

types/react/index.d.ts

@@ -1599,7 +1599,7 @@ declare namespace React {
         /**
          * The position property controls the type of positioning used by an element within its parent elements. The effect of the position property depends on a lot of factors, for example the position property of parent elements.
          */
-        position?: CSSWideKeyword | any;
+        position?: CSSWideKeyword | "static" | "relative" | "absolute" | "fixed" | "sticky";
 
         /**
          * Obsolete: unsupported.

types/react/test/cssProperties.tsx

@@ -30,6 +30,9 @@ const boxShadowStyleTest = <div style={boxShadowStyle} />;
 const overflowStyle: React.CSSProperties = { overflow: 'auto', overflowX: 'visible', overflowY: 'scroll' };
 const overflowStyleTest = <div style={overflowStyle} />;
 
+const positionStyle: React.CSSProperties = { position: 'relative' };
+const positionStyleTest = <div style={positionStyle} />;
+
 // SVG specific style attribute declarations
 
 const fillOpacityStyle: React.CSSProperties = { fillOpacity: 0.3 };